Growth Cones: Bulbous enlargement of the growing tip of nerve axons and dendrites. They are crucial to neuronal development because of their pathfinding ability and their role in synaptogenesis.Nerve Regeneration: Renewal or physiological repair of damaged nerve tissue.Decapodiformes: A superorder of CEPHALOPODS comprised of squid, cuttlefish, and their relatives. Their distinguishing feature is the modification of their fourth pair of arms into tentacles, resulting in 10 limbs.Axonal Transport: The directed transport of ORGANELLES and molecules along nerve cell AXONS. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (Alberts et al., Molecular Biology of the Cell, 3d ed, pG3)Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Motor Neurons: Neurons which activate MUSCLE CELLS.Myelin Sheath: The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.Optic Nerve: The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.Nerve Tissue ProteinsSpinal Cord: A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.Retinal Ganglion Cells: Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.Dendrites: Extensions of the nerve cell body. They are short and branched and receive stimuli from other NEURONS.Schwann Cells: Neuroglial cells of the peripheral nervous system which form the insulating myelin sheaths of peripheral axons.Optic Chiasm: The X-shaped structure formed by the meeting of the two optic nerves. At the optic chiasm the fibers from the medial part of each retina cross to project to the other side of the brain while the lateral retinal fibers continue on the same side. As a result each half of the brain receives information about the contralateral visual field from both eyes.Neural Conduction: The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.Semaphorins: A family of proteins that mediate axonal guidance. Semaphorins act as repulsive cues for neuronal GROWTH CONES and bind to receptors on their filopodia. At least 20 different molecules have been described and divided into eight classes based on domain organization and species of origin. Classes 1 and 2 are invertebrate, classes 3-7 are vertebrate, and class V are viral. Semaphorins may be secreted (classes 2, 3, and V), transmembrane (classes 1, 4, 5, and 6), or membrane-anchored (class 7). All semaphorins possess a common 500-amino acid extracellular domain which is critical for receptor binding and specificity, and is also found in plexins and scatter factor receptors. Their C termini are class-specific and may contain additional sequence motifs.Wallerian Degeneration: Degeneration of distal aspects of a nerve axon following injury to the cell body or proximal portion of the axon. The process is characterized by fragmentation of the axon and its MYELIN SHEATH.Semaphorin-3A: The prototypical and most well-studied member of the semaphorin family. Semaphorin-3A is an axon-repulsive guidance cue for migrating neurons in the developing nervous system. It has so far been found only in vertebrates, and binds to NEUROPILIN-1/plexin complex receptors on growth cones. Like other class 3 semaphorins, it is a secreted protein.Neurites: In tissue culture, hairlike projections of neurons stimulated by growth factors and other molecules. These projections may go on to form a branched tree of dendrites or a single axon or they may be reabsorbed at a later stage of development. "Neurite" may refer to any filamentous or pointed outgrowth of an embryonal or tissue-culture neural cell.Neurons, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Central Nervous System: The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.Ganglia, Spinal: Sensory ganglia located on the dorsal spinal roots within the vertebral column. The spinal ganglion cells are pseudounipolar. The single primary branch bifurcates sending a peripheral process to carry sensory information from the periphery and a central branch which relays that information to the spinal cord or brain.Synapses: Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.Peripheral Nerves: The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.Superior Colliculi: The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.Nerve Growth Factors: Factors which enhance the growth potentialities of sensory and sympathetic nerve cells.Retina: The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Nerve Fibers, Myelinated: A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.GAP-43 Protein: A nervous tissue specific protein which is highly expressed in NEURONS during development and NERVE REGENERATION. It has been implicated in neurite outgrowth, long-term potentiation, SIGNAL TRANSDUCTION, and NEUROTRANSMITTER release. (From Neurotoxicology 1994;15(1):41-7) It is also a substrate of PROTEIN KINASE C.Sensory Receptor Cells: Specialized afferent neurons capable of transducing sensory stimuli into NERVE IMPULSES to be transmitted to the CENTRAL NERVOUS SYSTEM. Sometimes sensory receptors for external stimuli are called exteroceptors; for internal stimuli are called interoceptors and proprioceptors.Axotomy: Transection or severing of an axon. This type of denervation is used often in experimental studies on neuronal physiology and neuronal death or survival, toward an understanding of nervous system disease.Neuroglia: The non-neuronal cells of the nervous system. They not only provide physical support, but also respond to injury, regulate the ionic and chemical composition of the extracellular milieu, participate in the BLOOD-BRAIN BARRIER and BLOOD-RETINAL BARRIER, form the myelin insulation of nervous pathways, guide neuronal migration during development, and exchange metabolites with neurons. Neuroglia have high-affinity transmitter uptake systems, voltage-dependent and transmitter-gated ion channels, and can release transmitters, but their role in signaling (as in many other functions) is unclear.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.Ranvier's Nodes: Regularly spaced gaps in the myelin sheaths of peripheral axons. Ranvier's nodes allow saltatory conduction, that is, jumping of impulses from node to node, which is faster and more energetically favorable than continuous conduction.Visual Pathways: Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Presynaptic Terminals: The distal terminations of axons which are specialized for the release of neurotransmitters. Also included are varicosities along the course of axons which have similar specializations and also release transmitters. Presynaptic terminals in both the central and peripheral nervous systems are included.Horseradish Peroxidase: An enzyme isolated from horseradish which is able to act as an antigen. It is frequently used as a histochemical tracer for light and electron microscopy. Its antigenicity has permitted its use as a combined antigen and marker in experimental immunology.Nerve Crush: Treatment of muscles and nerves under pressure as a result of crush injuries.Chick Embryo: The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.Animals, Genetically Modified: ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Nervous System: The entire nerve apparatus, composed of a central part, the brain and spinal cord, and a peripheral part, the cranial and spinal nerves, autonomic ganglia, and plexuses. (Stedman, 26th ed)Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Nerve Degeneration: Loss of functional activity and trophic degeneration of nerve axons and their terminal arborizations following the destruction of their cells of origin or interruption of their continuity with these cells. The pathology is characteristic of neurodegenerative diseases. Often the process of nerve degeneration is studied in research on neuroanatomical localization and correlation of the neurophysiology of neural pathways.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Neuropilin-1: Dimeric cell surface receptor involved in angiogenesis (NEOVASCULARIZATION, PHYSIOLOGICAL) and axonal guidance. Neuropilin-1 is a 140-kDa transmembrane protein that binds CLASS 3 SEMAPHORINS, and several other growth factors. Neuropilin-1 forms complexes with plexins or VEGF RECEPTORS, and binding affinity and specificity are determined by the composition of the neuropilin dimer and the identity of other receptors complexed with it. Neuropilin-1 is expressed in distinct patterns during neural development, complementary to those described for NEUROPILIN-2.Contactin 2: A contactin subtype that plays a role in axon outgrowth, axon fasciculation, and neuronal migration.Diencephalon: The paired caudal parts of the PROSENCEPHALON from which the THALAMUS; HYPOTHALAMUS; EPITHALAMUS; and SUBTHALAMUS are derived.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Animals, Newborn: Refers to animals in the period of time just after birth.Olfactory Nerve: The 1st cranial nerve. The olfactory nerve conveys the sense of smell. It is formed by the axons of OLFACTORY RECEPTOR NEURONS which project from the olfactory epithelium (in the nasal epithelium) to the OLFACTORY BULB.Spinal Nerve Roots: Paired bundles of NERVE FIBERS entering and leaving the SPINAL CORD at each segment. The dorsal and ventral nerve roots join to form the mixed segmental spinal nerves. The dorsal roots are generally afferent, formed by the central projections of the spinal (dorsal root) ganglia sensory cells, and the ventral roots are efferent, comprising the axons of spinal motor and PREGANGLIONIC AUTONOMIC FIBERS.Green Fluorescent Proteins: Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.Astacoidea: A superfamily of various freshwater CRUSTACEA, in the infraorder Astacidea, comprising the crayfish. Common genera include Astacus and Procambarus. Crayfish resemble lobsters, but are usually much smaller.Zebrafish: An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Olfactory Bulb: Ovoid body resting on the CRIBRIFORM PLATE of the ethmoid bone where the OLFACTORY NERVE terminates. The olfactory bulb contains several types of nerve cells including the mitral cells, on whose DENDRITES the olfactory nerve synapses, forming the olfactory glomeruli. The accessory olfactory bulb, which receives the projection from the VOMERONASAL ORGAN via the vomeronasal nerve, is also included here.Peripheral Nervous System: The nervous system outside of the brain and spinal cord. The peripheral nervous system has autonomic and somatic divisions. The autonomic nervous system includes the enteric, parasympathetic, and sympathetic subdivisions. The somatic nervous system includes the cranial and spinal nerves and their ganglia and the peripheral sensory receptors.Drosophila: A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.Mollusca: A phylum of the kingdom Metazoa. Mollusca have soft, unsegmented bodies with an anterior head, a dorsal visceral mass, and a ventral foot. Most are encased in a protective calcareous shell. It includes the classes GASTROPODA; BIVALVIA; CEPHALOPODA; Aplacophora; Scaphopoda; Polyplacophora; and Monoplacophora.Nerve Endings: Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.Thalamus: Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.Ephrin-A2: A GLYCOINOSITOL PHOSPHOLIPID MEMBRANE ANCHOR-containing ephrin with a high affinity for the EPHA3 RECEPTOR. Early in embryogenesis it is expressed at high levels in the MESENCEPHALON; SOMITES; branchial arches, and LIMB BUDS.Cerebral Cortex: The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulchi. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.Receptors, Eph Family: A large family of receptor protein-tyrosine kinases that are structurally-related. The name of this family of proteins derives from original protein Eph (now called the EPHA1 RECEPTOR), which was named after the cell line it was first discovered in: Erythropoietin-Producing human Hepatocellular carcinoma cell line. Members of this family have been implicated in regulation of cell-cell interactions involved in nervous system patterning and development.Pyramidal Tracts: Fibers that arise from cells within the cerebral cortex, pass through the medullary pyramid, and descend in the spinal cord. Many authorities say the pyramidal tracts include both the corticospinal and corticobulbar tracts.Myelin Proteins: MYELIN-specific proteins that play a structural or regulatory role in the genesis and maintenance of the lamellar MYELIN SHEATH structure.Fasciculation: Involuntary contraction of the muscle fibers innervated by a motor unit. Fasciculations can often by visualized and take the form of a muscle twitch or dimpling under the skin, but usually do not generate sufficient force to move a limb. They may represent a benign condition or occur as a manifestation of MOTOR NEURON DISEASE or PERIPHERAL NERVOUS SYSTEM DISEASES. (Adams et al., Principles of Neurology, 6th ed, p1294)Interneurons: Most generally any NEURONS which are not motor or sensory. Interneurons may also refer to neurons whose AXONS remain within a particular brain region in contrast to projection neurons, which have axons projecting to other brain regions.Ephrin-A5: A GLYCOINOSITOL PHOSPHOLIPID MEMBRANE ANCHOR containing ephrin found in developing tectum. It has been shown to mediate the bundling of cortical axons and repel the axonal growth of retinal ganglia axons. It is found in a variety of adult tissues of BRAIN; HEART; and KIDNEY.Oligodendroglia: A class of large neuroglial (macroglial) cells in the central nervous system. Oligodendroglia may be called interfascicular, perivascular, or perineuronal (not the same as SATELLITE CELLS, PERINEURONAL of GANGLIA) according to their location. They form the insulating MYELIN SHEATH of axons in the central nervous system.Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.Olfactory Pathways: Set of nerve fibers conducting impulses from olfactory receptors to the cerebral cortex. It includes the OLFACTORY NERVE; OLFACTORY BULB; OLFACTORY TRACT; OLFACTORY TUBERCLE; ANTERIOR PERFORATED SUBSTANCE; and OLFACTORY CORTEX.Embryo, Nonmammalian: The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.Spinal Cord Injuries: Penetrating and non-penetrating injuries to the spinal cord resulting from traumatic external forces (e.g., WOUNDS, GUNSHOT; WHIPLASH INJURIES; etc.).Trochlear Nerve: The 4th cranial nerve. The trochlear nerve carries the motor innervation of the superior oblique muscles of the eye.Synaptic Transmission: The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Hippocampus: A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.Neurogenesis: Formation of NEURONS which involves the differentiation and division of STEM CELLS in which one or both of the daughter cells become neurons.Models, Neurological: Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Afferent Pathways: Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.Efferent Pathways: Nerve structures through which impulses are conducted from a nerve center toward a peripheral site. Such impulses are conducted via efferent neurons (NEURONS, EFFERENT), such as MOTOR NEURONS, autonomic neurons, and hypophyseal neurons.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Neuropilin-2: Transmembrane receptor for CLASS 3 SEMAPHORINS and several vascular endothelial growth factor isoforms. Neuropilin-2 functions either as a homodimer or as a heterodimer with NEUROPILIN-1. The binding affinity of neuropilin-2 varies for different class 3 semaphorin isoforms and is dependent on the composition of the dimer. The protein also forms receptor complexes with plexins and with VEGF RECEPTORS, which alters the binding characteristics of the receptor.Microtubules: Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Polychaeta: A class of marine annelids including sandworms, tube worms, clamworms, and fire worms. It includes also the genus Myxicola infundibulum.Tectum Mesencephali: The dorsal portion or roof of the midbrain which is composed of two pairs of bumps, the INFERIOR COLLICULI and the SUPERIOR COLLICULI. These four colliculi are also called the quadrigeminal bodies (TECTUM MESENCEPHALI). They are centers for visual sensorimotor integration.Ganglia: Clusters of multipolar neurons surrounded by a capsule of loosely organized CONNECTIVE TISSUE located outside the CENTRAL NERVOUS SYSTEM.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Olfactory Receptor Neurons: Neurons in the OLFACTORY EPITHELIUM with proteins (RECEPTORS, ODORANT) that bind, and thus detect, odorants. These neurons send their DENDRITES to the surface of the epithelium with the odorant receptors residing in the apical non-motile cilia. Their unmyelinated AXONS synapse in the OLFACTORY BULB of the BRAIN.Mice, Inbred C57BLEmbryo, Mammalian: The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Caenorhabditis elegans Proteins: Proteins from the nematode species CAENORHABDITIS ELEGANS. The proteins from this species are the subject of scientific interest in the area of multicellular organism MORPHOGENESIS.Neural Cell Adhesion Molecules: Cell adhesion molecule involved in a diverse range of contact-mediated interactions among neurons, astrocytes, oligodendrocytes, and myotubes. It is widely but transiently expressed in many tissues early in embryogenesis. Four main isoforms exist, including CD56; (ANTIGENS, CD56); but there are many other variants resulting from alternative splicing and post-translational modifications. (From Pigott & Power, The Adhesion Molecule FactsBook, 1993, pp115-119)Caenorhabditis elegans: A species of nematode that is widely used in biological, biochemical, and genetic studies.Microscopy, Confocal: A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.Neuromuscular Junction: The synapse between a neuron and a muscle.Stilbamidines: STILBENES with AMIDINES attached.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Electroporation: A technique in which electric pulses of intensity in kilovolts per centimeter and of microsecond-to-millisecond duration cause a temporary loss of the semipermeability of CELL MEMBRANES, thus leading to ion leakage, escape of metabolites, and increased uptake by cells of drugs, molecular probes, and DNA.Tubulin: A microtubule subunit protein found in large quantities in mammalian brain. It has also been isolated from SPERM FLAGELLUM; CILIA; and other sources. Structurally, the protein is a dimer with a molecular weight of approximately 120,000 and a sedimentation coefficient of 5.8S. It binds to COLCHICINE; VINCRISTINE; and VINBLASTINE.Carbocyanines: Compounds that contain three methine groups. They are frequently used as cationic dyes used for differential staining of biological materials.Optic Lobe, Nonmammalian: In invertebrate zoology, a lateral lobe of the FOREBRAIN in certain ARTHROPODS. In vertebrate zoology, either of the corpora bigemina of non-mammalian VERTEBRATES. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1329)Nicotinamide-Nucleotide Adenylyltransferase: An enzyme that catalyzes reversibly the transfer of the adenylyl moiety of ATP to the phosphoryl group of NMN to form NAD+ and pyrophosphate. The enzyme is found predominantly in the nuclei and catalyzes the final reaction in the major pathway for the biosynthesis of NAD in mammals. EC 2.7.7.1.Superior Cervical Ganglion: The largest and uppermost of the paravertebral sympathetic ganglia.Demyelinating Diseases: Diseases characterized by loss or dysfunction of myelin in the central or peripheral nervous system.Zebrafish Proteins: Proteins obtained from the ZEBRAFISH. Many of the proteins in this species have been the subject of studies involving basic embryological development (EMBRYOLOGY).Cerebellum: The part of brain that lies behind the BRAIN STEM in the posterior base of skull (CRANIAL FOSSA, POSTERIOR). It is also known as the "little brain" with convolutions similar to those of CEREBRAL CORTEX, inner white matter, and deep cerebellar nuclei. Its function is to coordinate voluntary movements, maintain balance, and learn motor skills.Chondroitin ABC Lyase: An enzyme that catalyzes the eliminative degradation of polysaccharides containing 1,4-beta-D-hexosaminyl and 1,3-beta-D-glucuronosyl or 1,3-alpha-L-iduronosyl linkages to disaccharides containing 4-deoxy-beta-D-gluc-4-enuronosyl groups. (Enzyme Nomenclature, 1992)Optic Nerve Injuries: Injuries to the optic nerve induced by a trauma to the face or head. These may occur with closed or penetrating injuries. Relatively minor compression of the superior aspect of orbit may also result in trauma to the optic nerve. Clinical manifestations may include visual loss, PAPILLEDEMA, and an afferent pupillary defect.In Situ Hybridization: A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.Mice, Neurologic Mutants: Mice which carry mutant genes for neurologic defects or abnormalities.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Cell Movement: The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.Tetrodotoxin: An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Rhombencephalon: The posterior of the three primitive cerebral vesicles of an embryonic brain. It consists of myelencephalon, metencephalon, and isthmus rhombencephali from which develop the major BRAIN STEM components, such as MEDULLA OBLONGATA from the myelencephalon, CEREBELLUM and PONS from the metencephalon, with the expanded cavity forming the FOURTH VENTRICLE.Microscopy, Electron, Transmission: Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.Nerve Tissue: Differentiated tissue of the central nervous system composed of NERVE CELLS, fibers, DENDRITES, and specialized supporting cells.Goldfish: Common name for Carassius auratus, a type of carp (CARPS).Neuronal Plasticity: The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.Prosencephalon: The anterior of the three primitive cerebral vesicles of the embryonic brain arising from the NEURAL TUBE. It subdivides to form DIENCEPHALON and TELENCEPHALON. (Stedmans Medical Dictionary, 27th ed)Sodium Channels: Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.Telencephalon: The anterior subdivision of the embryonic PROSENCEPHALON or the corresponding part of the adult prosencephalon that includes the cerebrum and associated structures.Organ Culture Techniques: A technique for maintenance or growth of animal organs in vitro. It refers to three-dimensional cultures of undisaggregated tissue retaining some or all of the histological features of the tissue in vivo. (Freshney, Culture of Animal Cells, 3d ed, p1)Retrograde Degeneration: Pathologic changes that occur in the axon and cell body of a neuron proximal to an axonal lesion. The process is characterized by central chromatolysis which features flattening and displacement of the nucleus, loss of Nissl bodies, and cellular edema. Central chromatolysis primarily occurs in lower motor neurons.Body Patterning: The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.Photoreceptor Cells, Invertebrate: Specialized cells in the invertebrates that detect and transduce light. They are predominantly rhabdomeric with an array of photosensitive microvilli. Illumination depolarizes invertebrate photoreceptors by stimulating Na+ influx across the plasma membrane.Neuropil: A dense intricate feltwork of interwoven fine glial processes, fibrils, synaptic terminals, axons, and dendrites interspersed among the nerve cells in the gray matter of the central nervous system.Ganglia, Sympathetic: Ganglia of the sympathetic nervous system including the paravertebral and the prevertebral ganglia. Among these are the sympathetic chain ganglia, the superior, middle, and inferior cervical ganglia, and the aorticorenal, celiac, and stellate ganglia.Geniculate Bodies: Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.Crustacea: A large subphylum of mostly marine ARTHROPODS containing over 42,000 species. They include familiar arthropods such as lobsters (NEPHROPIDAE), crabs (BRACHYURA), shrimp (PENAEIDAE), and barnacles (THORACICA).Peripheral Nerve Injuries: Injuries to the PERIPHERAL NERVES.Receptor, EphA5: An eph family receptor found primarily in differentiated neuronal tissues. Several isoforms of EphA5 receptor occur due to multiple alternative RNA splicing. The protein is prominently expressed in the NEURONS of the LIMBIC SYSTEM during development and throughout adult life, suggesting its role in the plasticity of limbic structure and function.Receptor, EphA4: An eph family receptor found in variety of tissues including BRAIN. During embryogenesis, EphA4 receptor exhibits a diverse spatial and temporal patterns of expression suggesting its role in multiple developmental processes.Sciatic Neuropathy: Disease or damage involving the SCIATIC NERVE, which divides into the PERONEAL NERVE and TIBIAL NERVE (see also PERONEAL NEUROPATHIES and TIBIAL NEUROPATHY). Clinical manifestations may include SCIATICA or pain localized to the hip, PARESIS or PARALYSIS of posterior thigh muscles and muscles innervated by the peroneal and tibial nerves, and sensory loss involving the lateral and posterior thigh, posterior and lateral leg, and sole of the foot. The sciatic nerve may be affected by trauma; ISCHEMIA; COLLAGEN DISEASES; and other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1363)Denervation: The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)Cell Communication: Any of several ways in which living cells of an organism communicate with one another, whether by direct contact between cells or by means of chemical signals carried by neurotransmitter substances, hormones, and cyclic AMP.Microscopy, Immunoelectron: Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.Leeches: Annelids of the class Hirudinea. Some species, the bloodsuckers, may become temporarily parasitic upon animals, including man. Medicinal leeches (HIRUDO MEDICINALIS) have been used therapeutically for drawing blood since ancient times.Cell Count: The number of CELLS of a specific kind, usually measured per unit volume or area of sample.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Motor Neurons, Gamma: Motor neurons which activate the contractile regions of intrafusal SKELETAL MUSCLE FIBERS, thus adjusting the sensitivity of the MUSCLE SPINDLES to stretch. Gamma motor neurons may be "static" or "dynamic" according to which aspect of responsiveness (or which fiber types) they regulate. The alpha and gamma motor neurons are often activated together (alpha gamma coactivation) which allows the spindles to contribute to the control of movement trajectories despite changes in muscle length.Muscle Spindles: Skeletal muscle structures that function as the MECHANORECEPTORS responsible for the stretch or myotactic reflex (REFLEX, STRETCH). They are composed of a bundle of encapsulated SKELETAL MUSCLE FIBERS, i.e., the intrafusal fibers (nuclear bag 1 fibers, nuclear bag 2 fibers, and nuclear chain fibers) innervated by SENSORY NEURONS.Lampreys: Common name for the only family (Petromyzontidae) of eellike fish in the order Petromyzontiformes. They are jawless but have a sucking mouth with horny teeth.Larva: Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Receptor, EphA1: The founding member of the EPH FAMILY RECEPTORS. It was first cloned from an erythropoietin-producing human hepatocellular carcinoma cell line and is highly conserved among many mammalian species. Overproduction of the EphA1 receptor is associated with tumors and tumor cells of epithelial origin. It is also expressed at high levels in LIVER; LUNG; and KIDNEY; which is in contrast to many other members of the Eph receptor that are found primarily in tissues of the nervous system.Ankyrins: A family of membrane-associated proteins responsible for the attachment of the cytoskeleton. Erythrocyte-related isoforms of ankyrin attach the SPECTRIN cytoskeleton to a transmembrane protein (ANION EXCHANGE PROTEIN 1, ERYTHROCYTE) in the erythrocyte plasma membrane. Brain-related isoforms of ankyrin also exist.Oculomotor Nerve: The 3d cranial nerve. The oculomotor nerve sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye. It also sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation. The motor fibers originate in the oculomotor nuclei of the midbrain.Myelin-Associated Glycoprotein: A myelin protein found in the periaxonal membrane of both the central and peripheral nervous systems myelin sheaths. It binds to cells surface receptors found on AXONS and may regulate cellular interactions between MYELIN and AXONS.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.Grasshoppers: Plant-eating orthopterans having hindlegs adapted for jumping. There are two main families: Acrididae and Romaleidae. Some of the more common genera are: Melanoplus, the most common grasshopper; Conocephalus, the eastern meadow grasshopper; and Pterophylla, the true katydid.Cell Adhesion Molecules, Neuron-Glia: Cell adhesion molecules that mediate neuron-neuron adhesion and neuron-astrocyte adhesion. They are expressed on neurons and Schwann cells, but not astrocytes and are involved in neuronal migration, neurite fasciculation, and outgrowth. Ng-CAM is immunologically and structurally distinct from NCAM.Microtubule-Associated Proteins: High molecular weight proteins found in the MICROTUBULES of the cytoskeletal system. Under certain conditions they are required for TUBULIN assembly into the microtubules and stabilize the assembled microtubules.gamma-Aminobutyric Acid: The most common inhibitory neurotransmitter in the central nervous system.Receptors, Immunologic: Cell surface molecules on cells of the immune system that specifically bind surface molecules or messenger molecules and trigger changes in the behavior of cells. Although these receptors were first identified in the immune system, many have important functions elsewhere.Cerebellar Cortex: The superficial GRAY MATTER of the CEREBELLUM. It consists of two main layers, the stratum moleculare and the stratum granulosum.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Neuroanatomical Tract-Tracing Techniques: Methods used to label and follow the course of NEURAL PATHWAYS by AXONAL TRANSPORT of injected NEURONAL TRACT-TRACERS.Ephrin-B3: A transmembrane domain containing ephrin. Although originally found to be specific for the EPHB3 RECEPTOR it has since been shown to bind a variety of EPH FAMILY RECEPTORS. During embryogenesis ephrin-B3 is expressed at high levels in the ventral neural tube. In adult tissues, it is found primarily in the BRAIN and HEART.Luminescent Proteins: Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.Neurons, Efferent: Neurons which send impulses peripherally to activate muscles or secretory cells.Muscles: Contractile tissue that produces movement in animals.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Nephropidae: Family of large marine CRUSTACEA, in the order DECAPODA. These are called clawed lobsters because they bear pincers on the first three pairs of legs. The American lobster and Cape lobster in the genus Homarus are commonly used for food.Cell Adhesion Molecules: Surface ligands, usually glycoproteins, that mediate cell-to-cell adhesion. Their functions include the assembly and interconnection of various vertebrate systems, as well as maintenance of tissue integration, wound healing, morphogenic movements, cellular migrations, and metastasis.Receptor, EphA3: An eph family receptor that is found primarily in adult BRAIN and variety of tissues in the developing embryo tissues. During embryonic development high levels of EphA3 receptor expression is seen in the nervous system and coincides with neuronal cell migration, suggesting a role for this protein in axonal pathfinding.Neural Cell Adhesion Molecule L1: A member of the immunoglobulin superfamily of neuronal cell adhesion molecules that is required for proper nervous system development. Neural cell adhesion molecule L1 consists of six Ig domains, five fibronectin domains, a transmembrane region and an intracellular domain. Two splicing variants are known: a neuronal form that contains a four-amino acid RSLE sequence in the cytoplasmic domain, and a non-neuronal form that lacks the RSLE sequence. Mutations in the L1 gene result in L1 disease. Neural cell adhesion molecule L1 is predominantly expressed during development in neurons and Schwann cells; involved in cell adhesion, neuronal migration, axonal growth and pathfinding, and myelination.Cranial Nerves: Twelve pairs of nerves that carry general afferent, visceral afferent, special afferent, somatic efferent, and autonomic efferent fibers.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Hindlimb: Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.Neocortex: The largest portion of the CEREBRAL CORTEX in which the NEURONS are arranged in six layers in the mammalian brain: molecular, external granular, external pyramidal, internal granular, internal pyramidal and multiform layers.Brain-Derived Neurotrophic Factor: A member of the nerve growth factor family of trophic factors. In the brain BDNF has a trophic action on retinal, cholinergic, and dopaminergic neurons, and in the peripheral nervous system it acts on both motor and sensory neurons. (From Kendrew, The Encyclopedia of Molecular Biology, 1994)Histocytochemistry: Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.Pyramidal Cells: Projection neurons in the CEREBRAL CORTEX and the HIPPOCAMPUS. Pyramidal cells have a pyramid-shaped soma with the apex and an apical dendrite pointed toward the pial surface and other dendrites and an axon emerging from the base. The axons may have local collaterals but also project outside their cortical region.Nervous System Malformations: Structural abnormalities of the central or peripheral nervous system resulting primarily from defects of embryogenesis.Nerve Fibers, Unmyelinated: A class of nerve fibers as defined by their nerve sheath arrangement. The AXONS of the unmyelinated nerve fibers are small in diameter and usually several are surrounded by a single MYELIN SHEATH. They conduct low-velocity impulses, and represent the majority of peripheral sensory and autonomic fibers, but are also found in the BRAIN and SPINAL CORD.Autonomic Fibers, Preganglionic: NERVE FIBERS which project from the central nervous system to AUTONOMIC GANGLIA. In the sympathetic division most preganglionic fibers originate with neurons in the intermediolateral column of the SPINAL CORD, exit via ventral roots from upper thoracic through lower lumbar segments, and project to the paravertebral ganglia; there they either terminate in SYNAPSES or continue through the SPLANCHNIC NERVES to the prevertebral ganglia. In the parasympathetic division the fibers originate in neurons of the BRAIN STEM and sacral spinal cord. In both divisions the principal transmitter is ACETYLCHOLINE but peptide cotransmitters may also be released.Cell Polarity: Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.Eye: The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.Time-Lapse Imaging: Recording serial images of a process at regular intervals spaced out over a longer period of time than the time in which the recordings will be played back.Mechanoreceptors: Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.Purkinje Cells: The output neurons of the cerebellar cortex.Microscopy, Fluorescence: Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.Neuronal Tract-Tracers: Substances used to identify the location and to characterize the types of NEURAL PATHWAYS.Evoked Potentials: Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.Trigeminal Nerve: The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the TRIGEMINAL GANGLION and project to the TRIGEMINAL NUCLEUS of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication.Brain Stem: The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Peroneal Nerve: The lateral of the two terminal branches of the sciatic nerve. The peroneal (or fibular) nerve provides motor and sensory innervation to parts of the leg and foot.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Nerve Growth Factor: NERVE GROWTH FACTOR is the first of a series of neurotrophic factors that were found to influence the growth and differentiation of sympathetic and sensory neurons. It is comprised of alpha, beta, and gamma subunits. The beta subunit is responsible for its growth stimulating activity.

Morphogenesis of callosal arbors in the parietal cortex of hamsters. (1/10970)

The morphogenesis of callosal axons originating in the parietal cortex was studied by anterograde labeling with Phaseolus lectin or biocytin injected in postnatal (P) hamsters aged 7-25 days. Some labeled fibers were serially reconstructed. At P7, some callosal fibers extended as far as the contralateral rhinal fissure, with simple arbors located in the homotopic region of the opposite cortical gray matter, and two or three unbranched sprouts along their trajectory. From P7 to P13, the homotopic arbors became more complex, with branches focused predominantly, but not exclusively, in the supra- and infragranular layers of the homotopic region. Simultaneously, the lateral extension of the trunk axon in the white matter became shorter, finally disappearing by P25. Arbors in the gray matter were either bilaminar (layers 2/3 and 5) or supragranular. A heterotopic projection to the lateral cortex was consistently seen at all ages; the heterotopic arbors follow a similar sequence of events to that seen in homotopic regions. These observations document that callosal axons undergo regressive tangential remodeling during the first postnatal month, as the lateral extension of the trunk fiber gets eliminated. Radially, however, significant arborization occurs in layer-specific locations. The protracted period of morphogenesis suggests a correspondingly long plastic period for this system of cortical fibers.  (+info)

Trans-synaptically induced bursts in regular spiking non-pyramidal cells in deep layers of the cat motor cortex. (2/10970)

In deep layers of the cat motor cortex, we have investigated the properties of neurons displaying trans-synaptically induced bursts. In in vivo experiments, extracellularly recorded burst neurons were separated into two subtypes based on their dependence on stimulation sites, the medullary pyramid or the ventrolateral (VL) thalamic nucleus, from which bursts of 10-20 spikes were triggered. The spike amplitude attenuation and frequency adaptation during a burst were more prominent in pyramid-dependent burst neurons than in VL-dependent burst neurons. Intracellular recordings in in vivo experiments revealed that pyramid-dependent bursts emerged from a long-lasting depolarization, while each spike during a VL-dependent burst was narrow in half-width and was followed by a fast AHP, similar to fast spiking neurons. In in vitro slice experiments, intracellular recordings were obtained from neurons that displayed a burst of attenuated spikes emerging from a long-lasting depolarization, and were also obtained from fast spiking neurons. They were morphologically recovered to be multipolar cells with sparsely spiny dendrites and local axonal networks, suggesting that they are inhibitory interneurons. The multipolar neurons displaying bursts of attenuated spikes may mediate the recurrent inhibition of pyramidal tract cells.  (+info)

Central peptidergic neurons are hyperactive during collateral sprouting and inhibition of activity suppresses sprouting. (3/10970)

Little is known regarding the effect of chronic changes in neuronal activity on the extent of collateral sprouting by identified CNS neurons. We have investigated the relationship between activity and sprouting in oxytocin (OT) and vasopressin (VP) neurons of the hypothalamic magnocellular neurosecretory system (MNS). Uninjured MNS neurons undergo a robust collateral-sprouting response that restores the axon population of the neural lobe (NL) after a lesion of the contralateral MNS (). Simultaneously, lesioned rats develop chronic urinary hyperosmolality indicative of heightened neurosecretory activity. We therefore tested the hypothesis that sprouting MNS neurons are hyperactive by measuring changes in cell and nuclear diameters, OT and VP mRNA pools, and axonal cytochrome oxidase activity (COX). Each of these measures was significantly elevated during the period of most rapid axonal growth between 1 and 4 weeks after the lesion, confirming that both OT and VP neurons are hyperactive while undergoing collateral sprouting. In a second study the hypothesis that chronic inhibition of neuronal activity would interfere with the sprouting response was tested. Chronic hyponatremia (CH) was induced 3 d before the hypothalamic lesion and sustained for 4 weeks to suppress neurosecretory activity. CH abolished the lesion-induced increases in OT and VP mRNA pools and virtually eliminated measurable COX activity in MNS terminals. Counts of the total number of axon profiles in the NL revealed that CH also prevented axonal sprouting from occurring. These results are consistent with the hypothesis that increased neuronal activity is required for denervation-induced collateral sprouting to occur in the MNS.  (+info)

Somatic recording of GABAergic autoreceptor current in cerebellar stellate and basket cells. (4/10970)

Patch-clamp recordings were performed from stellate and basket cells in rat cerebellar slices. Under somatic voltage clamp, short depolarizing pulses were applied to elicit action potentials in the axon. After the action potential, a bicuculline- and Cd2+-sensitive current transient was observed. A similar response was obtained when eliciting axonal firing by extracellular stimulation. With an isotonic internal Cl- solution, the peak amplitude of this current varied linearly with the holding potential, yielding an extrapolated reversal potential of -20 to 0 mV. Unlike synaptic or autaptic GABAergic currents obtained in the same preparation, the current transient had a slow rise-time and a low variability between trials. This current was blocked when 10 mM BAPTA was included in the recording solution. In some experiments, the current transient elicited axonal action potentials. The current transient was reliably observed in animals aged 12-15 d, with a mean amplitude of 82 pA at -70 mV, but was small and rare in the age group 29-49 d. Numerical simulations could account for all properties of the current transient by assuming that an action potential activates a distributed GABAergic conductance in the axon. The actual conductance is probably restricted to release sites, with an estimated mean presynaptic current response of 10 pA per site (-70 mV, age 12-15 d). We conclude that in developing rats, stellate and basket cell axons have a high density of GABAergic autoreceptors and that a sizable fraction of the corresponding current can be measured from the soma.  (+info)

The amyloid precursor protein interacts with Go heterotrimeric protein within a cell compartment specialized in signal transduction. (5/10970)

The function of the beta-amyloid protein precursor (betaAPP), a transmembrane molecule involved in Alzheimer pathologies, is poorly understood. We recently reported the presence of a fraction of betaAPP in cholesterol and sphingoglycolipid-enriched microdomains (CSEM), a caveolae-like compartment specialized in signal transduction. To investigate whether betaAPP actually interferes with cell signaling, we reexamined the interaction between betaAPP and Go GTPase. In strong contrast with results obtained with reconstituted phospholipid vesicles (Okamoto et al., 1995), we find that incubating total neuronal membranes with 22C11, an antibody that recognizes an N-terminal betaAPP epitope, reduces high-affinity Go GTPase activity. This inhibition is specific of Galphao and is reproduced, in the absence of 22C11, by the addition of the betaAPP C-terminal domain but not by two distinct mutated betaAPP C-terminal domains that do not bind Galphao. This inhibition of Galphao GTPase activity by either 22C11 or wild-type betaAPP cytoplasmic domain suggests that intracellular interactions between betaAPP and Galphao could be regulated by extracellular signals. To verify whether this interaction is preserved in CSEM, we first used biochemical, immunocytochemical, and ultrastructural techniques to unambiguously confirm the colocalization of Galphao and betaAPP in CSEM. We show that inhibition of basal Galphao GTPase activity also occurs within CSEM and correlates with the coimmunoprecipitation of Galphao and betaAPP. The regulation of Galphao GTPase activity by betaAPP in a compartment specialized in signaling may have important consequences for our understanding of the physiopathological functions of betaAPP.  (+info)

Cellular sites for dynorphin activation of kappa-opioid receptors in the rat nucleus accumbens shell. (6/10970)

The nucleus accumbens (Acb) is prominently involved in the aversive behavioral aspects of kappa-opioid receptor (KOR) agonists, including its endogenous ligand dynorphin (Dyn). We examined the ultrastructural immunoperoxidase localization of KOR and immunogold labeling of Dyn to determine the major cellular sites for KOR activation in this region. Of 851 KOR-labeled structures sampled from a total area of 10,457 microm2, 63% were small axons and morphologically heterogenous axon terminals, 31% of which apposed Dyn-labeled terminals or also contained Dyn. Sixty-eight percent of the KOR-containing axon terminals formed punctate-symmetric or appositional contacts with unlabeled dendrites and spines, many of which received convergent input from terminals that formed asymmetric synapses. Excitatory-type terminals that formed asymmetric synapses with dendritic spines comprised 21% of the KOR-immunoreactive profiles. Dendritic spines within the neuropil were the major nonaxonal structures that contained KOR immunoreactivity. These spines also received excitatory-type synapses from unlabeled terminals and were apposed by Dyn-containing terminals. These results provide ultrastructural evidence that in the Acb shell (AcbSh), KOR agonists play a primary role in regulating the presynaptic release of Dyn and other neuromodulators that influence the output of spiny neurons via changes in the presynaptic release of or the postsynaptic responses to excitatory amino acids. The cellular distribution of KOR complements those described previously for the reward-associated mu- and delta-opioid receptors in the Acb shell.  (+info)

even-skipped determines the dorsal growth of motor axons in Drosophila. (7/10970)

Axon pathfinding and target choice are governed by cell type-specific responses to external cues. Here, we show that in the Drosophila embryo, motorneurons with targets in the dorsal muscle field express the homeobox gene even-skipped and that this expression is necessary and sufficient to direct motor axons into the dorsal muscle field. Previously, it was shown that motorneurons projecting to ventral targets express the LIM homeobox gene islet, which is sufficient to direct axons to the ventral muscle field. Thus, even-skipped complements the function of islet, and together these two genes constitute a bimodal switch regulating axonal growth and directing motor axons to ventral or to dorsal regions of the muscle field.  (+info)

Prior exposure to neurotrophins blocks inhibition of axonal regeneration by MAG and myelin via a cAMP-dependent mechanism. (8/10970)

MAG is a potent inhibitor of axonal regeneration. Here, inhibition by MAG, and myelin in general, is blocked if neurons are exposed to neurotrophins before encountering the inhibitor; priming cerebellar neurons with BDNF or GDNF, but not NGF, or priming DRG neurons with any of these neurotrophins blocks inhibition by MAG/myelin. Dibutyryl cAMP also overcomes inhibition by MAG/myelin, and cAMP is elevated by neurotrophins. A PKA inhibitor present during priming abrogates the block of inhibition. Finally, if neurons are exposed to MAG/myelin and neurotrophins simultaneously, but with the Gi protein inhibitor, inhibition is blocked. We suggest that priming neurons with particular neurotrophins elevates cAMP and activates PKA, which blocks subsequent inhibition of regeneration and that priming is required because MAG/myelin activates a Gi protein, which blocks increases in cAMP. This is important for encouraging axons to regrow in vivo.  (+info)

*Axon

Axons are covered by a membrane known as an axolemma; the cytoplasm of an axon is called axoplasm. Most axons branch, in some ... The axonal region or compartment, includes the axon hillock, the initial segment, the rest of the axon, and the axon ... yet only one of these neurites is destined to become the axon. It is unclear whether axon specification precedes axon ... An axon is one of two types of cytoplasmic protrusions from the cell body of a neuron; the other type is a dendrite. Axons are ...

*Axone

... may refer to: Axone (arena), sports arena in Montbéliard, France Yr. Robert Lalkovits - Axone, Hungarian musician Akhuni ... a fermented Indian soybean product Axon (disambiguation). ...

*Axon Automotive

Official Axon Automotive website "Axon Automotive to show 100mpg hatchback at Eden Project Sexy Green Car Show". Auto Industry ... Axon unveiled its 100 miles per imperial gallon (2.8 L/100 km; 83 mpg‑US) hatchback on 23 May 2008 at the Sexy Green Car Show ... Axon Automotive is a British car manufacturer and car components manufacturer based in Wellingborough, Northamptonshire. The ... Axon provides solutions for lightweight structural composite components for mainstream automotive and other high volume markets ...

*Axon guidance

Axons use mechanical and chemical cues to find their targets. Growing axons have a highly motile structure at the growing tip ... However, as axons approach the midline, the repellent action of Slit is suppressed by Robo-3/Rig-1 receptor. Once the axons ... Axon guidance (also called axon pathfinding) is a subfield of neural development concerning the process by which neurons send ... These axons follow a reproducible pathway, stop at intermediate targets, and branch axons at certain choice points, in the ...

*David Axon

Axon, D. J. and Taylor, K. (1978), M82: the exploding galaxy, Nature, 274, 37. Ray, T. P.; Muxlow, T. W. B., Axon, D. J., Brown ... David Axon died in 2012 of an apparent heart attack while visiting RIT. "Prof David Axon, Sussex School of Maths and Physics". ... "David Axon's homepage, RIT Physics Faculty & Staff". Retrieved 6 April 2012. Wilson, A. S., Ward, M. J, Axon, D. J., Elvis, M ... David Axon was born in Doncaster in the county of Yorkshire, England, to an English father and Welsh mother. He received a ...

*Axon (surname)

... grandson of John Axon the engine driver Rachael Axon (b. 1985), English footballer William Axon (1846-1913), English antiquary ... Axon is an English surname. Notable people with this surname include the following: Annemarie Carney Axon, American lawyer ... David Axon (1951-2012), British astrophysicist John Axon (1900-1957), English engine driver awarded the George Cross John Axon ...

*Pioneer axon

Subsequent axon-axon interactions were also shown to be necessary, as misrouting of retinal axons led to chiasm defasciculaiton ... The second is that pioneer axons are no different from follower axons, and that they play no role in guiding follower axons. ... Pioneer axon is the classification given to axons that are the first grow in a particular region. They originate from pioneer ... The directed growth of axons depends on structure at the end of the tip of a growing axon referred to as a growth cone. Growth ...

*Rachael Axon

... at Soccerway Rachel Axon profile at Houston Dash Rachel Axon profile at Football Association of Norway (in ... Rachael Louise Axon (born November 9, 1985) is an English footballer who plays for Norwegian club Kolbotn Fotball. She ... "Houston Dash waive midfielder Rachael Axon". Houston Dash. November 20, 2015. Retrieved November 28, 2015. ...

*Axon (disambiguation)

An axon is part of a neuron. Axon may also refer to: Corporations: Axon (company), American public safety technology company ... The Axons, an alien race from the Doctor Who adventure The Claws of Axos Peter Axon, a character in the series Psi Factor Axone ... Axon Automotive, British car manufacturer HCL Axon, British management consultants Axon Labs, American health & wellness ...

*HCL Axon

... is a UK-based business transformation consultancy which sells its services to customers using SAP and Oracle as their ... "HCL Axon buys UCS Group's SAP operation". HCL shifts focus from commodity IT to business Fitzpatrick, Jim (16 February 2012), " ... On 7 September 2005, HCL Axon expanded its operations base in the counties of Armagh and Belfast in Northern Ireland. At the ... On 17 July 2009 HCL AXON announced the acquisition of South Africa-based UCS Group's Enterprise Solutions SAP practice. On 1 ...

*Axon Sports

Axon has also released two iPad apps (Axon Athletic Brain Trainer), one for baseball and the other for American Football. ... Axon's product development is guided by the neuroscientists and learning specialists on the Axon Science Board. Current board ... Sport, Axon (25 August 2010). "Axon Sports CCAT system now available to assess cognitive function in children". News Medical ... In 2011, Cogstate acquired the remainder of the shares of Axon Sports from Quixote Investment, making Axon a wholly owned but ...

*Axon reflex

The impulse then reflects down the other branch of the axon to the effector organ causing axon reflex. Axon reflexes stimulate ... The axon reflex is the spread of this impulse from the main axon to nearby blood vessels in the stimulated area of the skin. ... In the axon reflex, signaling starts in the middle of the axon at the stimulation site and transmits signals directly to the ... The axon reflex is possible through the transmission of signals from the cutaneous receptors on the skin. The axon reflex was ...

*John Axon

The runaway smashed into the rear of it killing both the train's guard and Axon. Axon was posthumously awarded the George Cross ... Driver Axon told his Fireman Scanlon to jump off and attempt to apply wagon brakes but, due to the speed the train was ... John "Jack" Axon GC (4 December 1900 - 9 February 1957) was an English train driver from Stockport (Edgeley Depot) who died ... He was the subject of a famous 1957 radio ballad (The Ballad of John Axon), the first of the series, written by Ewan MacColl ...

*Axon terminal

The neurotransmitter molecule packages (vesicles) are created within the neuron, then travel down the axon to the distal axon ... of an axon. An axon, also called a nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts ... axon terminals are separated from neighboring neurons by a small gap called a synapse, across which impulses are sent. The axon ... "Axon Terminal". Medical Dictionary Online. Retrieved February 6, 2013. Foster, Sally. "Axon Terminal - Synaptic Vesicle - ...

*William Axon

William Edward Armytage Axon", The Times (1913) Works written by or about William Axon at Wikisource Works by William Axon at ... Completed by William E. A. Axon (1891) Obituary: Dr. William Edward Armytage Axon in The Times, December 30, 1913; Issue 40407 ... William Edward Armytage Axon (1846-1913) was an English librarian and antiquary, and a journalist for the Manchester Guardian. ... He contributed to the Dictionary of National Biography under his initials W. E. A. A. Dr William Axon was best known as an ...

*Axon hillock

The axon hillock is a specialized part of the cell body (or soma) of a neuron that connects to the axon. The axon hillock is ... Once this initial action potential is initiated, principally at the axon hillock, it propagates down the length of the axon. ... In electrophysiological models, the axon hillock is included with the initial segment of the axon where membrane potentials ... while the axon hillock and initial segment of the axon have about ~100-200 voltage-gated sodium channels per square micrometre ...

*Axone (arena)

L'Axone is an indoor arena, located in Montbéliard, France. It was inaugurated April 5, 2009. The capacity of the arena is 6,400 peoples ...

*John Axon (actor)

Axon was a Stockport County season ticket holder. He never married. Wylie, Ian (25 October 2008). "Royal star John Axon dies". ... John Axon (10 September 1960 - 25 October 2008) was an English television and stage actor. Axon trained at the Guildhall school ... Axon collapsed and died of a suspected heart attack near his home in Stockport on 25 October 2008 at the age of 48. He was ... Axon played Harper as a recurring role on the show from 2003 until 2005. Other television credits include prime suspect, city ...

*Squid giant axon

The squid giant axon is the very large (up to 1 mm in diameter; typically around 0.5 mm) axon that controls part of the water ... Action potentials travel faster in a larger axon than a smaller one,[page needed] and squid have evolved the giant axon to ... The increased diameter of the squid axon decreases the internal resistance of the axon, as resistance is inversely proportional ... While the squid axon is very large in diameter it is unmyelinated which decreases the conduction velocity substantially. The ...

*Annemarie Carney Axon

... (born 1973) is a member of the Birmingham law firm of Wallace, Jordan, Ratliff, & Brandt, LLC, where she ... On July 13, 2017, President Trump announced his intent to nominate Axon to serve as a United States District Judge of the ... On January 5, 2018 President Donald Trump announced his intent to renominate Axon to a federal judgeship. On January 8, 2018 ...

*Yr. Robert Lalkovits - Axone

Axone (Yr. Robert Lalkovits) is a famous composer, Hungarian songwriter, remix music producer and musician DJ based in Budapest ... Axone -Poker face remix with Lady Gaga. ...

*Threshold potential

... and properties of sodium channels within the axon all affect the threshold value. Typically in the axon or dendrite, there are ... Through use of voltage clamp techniques on a squid giant axon, they discovered that excitable tissues generally exhibit the ... These local graded potentials, which are primarily associated with external stimuli, reach the axon initial segment and build ... 3.0.CO;2-C. Burke, D; Kiernan, Matthew C; Bostock, Hugh (2001). "Excitability of human axons". Clinical Neuropysiology. 112 (9 ...

*Myelin

... ated axons are white; hence, the "white matter" of the brain. Myelin insulates axons from electrically charged atoms and ... Myelin is a fatty white substance that surrounds the axon of some nerve cells, forming an electrically insulating layer. It is ... However, the nodes in vertebrates are annular; i.e. they encircle the axon. In contrast, nodes found in the sheaths of ... This increases sodium's ability to travel along the axon more freely. However, the sodium diffuses along the axolemma rapidly, ...

*Paul Hetherington

"Editors , Axon". www.axonjournal.com.au. Retrieved 2017-03-18. "The Prose Poetry Project , Axon". www.axonjournal.com.au. ... He is co-founding editor of the international online journal Axon: Creative Explorations (2011-) and a founding editorial ... "Issue 11: Creative Work , Axon". www.axonjournal.com.au. Retrieved 2017-03-18. "The watchmaker's imprint : selected poems / Ian ... He is co-founder of the international journal Axon: Creative Explorations and founder of the International Prose Poetry Project ...

*Cassandra Atherton

"Issue 10: The Poetics of Collaboration , Axon". www.axonjournal.com.au. Retrieved 2017-03-14. Marshall, P. David; Atherton, ... Axon: Creative Explorations, (with Antonia Pont) (2016). Media International Australia, (with David Marshall) (2015). Mascara ...
The transcript encoding translationally controlled tumor protein (Tctp), a molecule correlated with aggressive breast cancers, was identified among the most abundant in genome-wide screens of axons, suggesting that Tctp is important in neurons. Here, we tested the role of Tctp in retinal axon development in Xenopus laevis. We report that Tctp deficiency results in stunted and splayed retinotectal projections that fail to innervate the optic tectum at the normal developmental time due to impaired axon extension. Tctp-deficient axons exhibit defects associated with mitochondrial dysfunction and we show that Tctp interacts in the axonal compartment with myeloid cell leukemia 1 (Mcl1), a pro-survival member of the Bcl-2 family. Mcl1 knockdown gives rise to similar axon misprojection phenotypes, and we provide evidence that Tctps anti-apoptotic activity is necessary for the normal development of the retinotectal projection. The findings suggest that Tctp supports the development of the retinotectal ...
Pathogenesis of the autoimmune disease multiple sclerosis (MS) is associated with progressive deterioration of the myelin sheath surrounding neuronal axons; however, axon damage may also contribute to MS-associated neurodegeneration. Nikić et al. used in vivo imaging and electron microscopy to examine axon damage in a mouse model of MS (EAE, experimental autoimmune encephalitis). In EAE mice, swelling in discrete sites on axons was observed, which was then followed by axon fragmentation. In many cases, damaged axons retained myelin; in some cases, axon damage was reversible. Axon damage was preceded by mitochondrial pathology, which was associated with the presence of microglia and the production of reactive oxygen and nitrogen species. Induction of oxidative or nitrosative stress was sufficient to induce mitochondrial pathology and axon damage in normal mice, and their blockade in EAE mice alleviated axon damage. Lesion biopsies from MS patients also showed similar axon (above, right) and ...
TY - JOUR. T1 - Dystroglycan is a scaffold for extracellular axon guidance decisions. AU - Lindenmaier, L. Bailey. AU - Parmentier, Nicolas. AU - Guo, Caiying. AU - Tissir, Fadel. AU - Wright, Kevin. PY - 2019/2/13. Y1 - 2019/2/13. N2 - Axon guidance requires interactions between extracellular signaling molecules and transmembrane receptors, but how appropriate context-dependent decisions are coordinated outside the cell remains unclear. Here we show that the transmembrane glycoprotein Dystroglycan interacts with a changing set of environmental cues that regulate the trajectories of extending axons throughout the mammalian brain and spinal cord. Dystroglycan operates primarily as an extracellular scaffold during axon guidance, as it functions non-cell autonomously and does not require signaling through its intracellular domain. We identify the transmembrane receptor Celsr3/Adgrc3 as a binding partner for Dystroglycan, and show that this interaction is critical for specific axon guidance events ...
Axonal localization of viral membrane proteins promoted by Us9 missense mutants correlates with degree of anterograde spread in the rodent nervous system. Neuro
The eye is a peripheral outpost of the central nervous system (CNS) where the retinal ganglion cells (RGCs) reside. RGC axons navigate to their targets in a remarkably stereotyped and error-free manner and it is this process of directed growth that underlies the complex organization of the adult brain. The RGCs are the only retinal neurons to project into the brain and their peripheral location makes them an unusually accessible population of projection neurons for experiments involving in vivo gene transfer, anatomical tracing, transplantation and in vitro culture. In this paper, we review recent findings that have contributed to our understanding of some of the guidance decisions that axons make in the developing visual system. We look at two choice points in the pathway, the optic nerve head (onh) and the midline chiasm, and discuss evidence that supports the idea that key molecules in guiding axon growth at these junctures are netrin-1 (onh) and ephrin-B (chiasm). In the optic tectum where RGC axon
zag-1 activity establishes several neuronal characteristics, such as cell position, axonal structure and gene-expression profile. Although zag-1 mutations confer various defects on sensory, motor and interneurons, common or related phenotypes are evident. These include the absence of stereotypic axon branches and upregulation of neurotransmitter biosynthetic and reuptake genes. zag-1 functions less to define neuron identity per se and more to generate features characteristic of a particular type of neuron. The specificity and selectivity of zag-1 phenotypes for each neuron type suggests that zag-1 acts in combination with other cell-type-specific factors to control differentiation.. SRA-6 is a candidate chemosensory receptor, based on its predicted seven transmembrane domain topology and expression in amphid sensory neurons ASH and ASI (Troemel et al., 1995). sra-6::gfp provides an ideal indicator of PVQ development and differentiation, although sra-6 function in interneuron PVQ is unclear. ...
This is a message to people interested (or potentially interested) in the development of the Drosophila motor axon system and CNS: I recently constructed a World Wide Web site (linked to our homepage, which is http://www.caltech.edu/~zinn/ ) on motor axon development in flies. This consists at present of a gallery of high-resolution Photoshop images (,35 images of antibody-stained embryos photographed with DIC optics, and several diagrams) of the neuromuscular system in embryos, with accompanying text. Most of the images in the current version are of wild-type embryos stained with the 1D4 antibody against Fasciclin II, which specifically labels motor axons (Van Vactor et al., Cell 73, 1137-1153 (1993)). The same segments are shown in several focal planes, so that the viewer can see the details of the pathways as if they were examining an actual embryo under the microscope. There are also embryos double-stained for PNS, muscle, and tracheal markers, so that motor axon development can be keyed to ...
In contrast to peripheral nerves, damaged axons of the mammalian brain and spinal cord rarely regenerate. Although the nature of the neuronal environment, particularly inhibitory molecules on myelin and in glial scar tissue, can partially explain the lack of regeneration in the CNS, intrinsic neuronal factors also have an influence. Intrinsic influences on axon growth are neuronal age (Lagunowich et al., 1992; Li et al., 1995), neuronal cell type (Benfey et al., 1985; Rossi et al., 2001), distance of axotomy from the cell body (Fernandes et al., 1999), and conditioning (McQuarrie, 1978; Neumann and Woolf, 1999). Thus, embryonic axons grow through environments that ordinarily block regeneration, some axons mount a vigorous regenerative response whereas some never regenerate, axons cut close to the cell body show a greater regenerative response than those cut more distally, and axons may regenerate with greater vigor if they have been damaged some days previously.. For successful regeneration, the ...
One of the most challenging problems in biology is to understand how the billions of neurons in the mammalian nervous system "wire up" to form functional neural circuits that underlie all behaviour. This has been one of the most intensely studied areas of developmental neurobiology in the past, and a number of important proteins have been identified that instruct axons to project to their specific target regions (so called axon guidance proteins).. Our current work focuses on how axon guidance proteins are detected by receptor proteins on growing axons, how these receptors signal and how they are regulated by for example endocytosis or proteolytic cleavage. Remarkably, our nervous system contains billions of connections but no more than a hundred axon guidance proteins. How can this relatively small number of proteins set up the wiring of a disproportionally large number of connections with many different characteristics such as trajectories or synaptic partners? Evidence is emerging that the ...
Nakamura, T., et al. (2017). Novel role of Rac-Mid1 signaling in medial cerebellar development. Development 144(10): 1863-1875. PubMed ID: 28512198 Nakaya, Y., Kuroda, S., Katagiri, Y. T., Kaibuchi, K. and Takahashi Y. (2004). Mesenchymal-epithelial transition during somitic segmentation is regulated by differential roles of Cdc42 and Rac1. Dev Cell. 7(3): 425-38. 15363416 Newsome, T. P., Schmidt, S., Dietzl, G., Keleman, K., Asling, B., Debant, A., and Dickson, B. J. (2000). Trio combines with Dock to regulate Pak activity during photoreceptor axon pathfinding in Drosophila. Cell 101: 283-94. PubMed Citation: 10847683 Ng, J., et al. (2002). Rac GTPases control axon growth, guidance and branching. Nature 416: 442-447. 11919635 Ng, J. and Luo, L. (2004). Rho GTPases regulate axon growth through convergent and divergent signaling pathways. Neuron 44: 779-793. 15572110 Ng, J. (2008). TGF-β signals regulate axonal development through distinct Smad-independent mechanisms. Development 135(24): ...
While commissural axons pathways are absent in comm mutants, other aspects of CNS development appear normal, including formation of longitudinal axon pathways, nerve roots, peripheral axon pathways, and peripheral sensory neurons. The mutant phenotype appears to be quite specific to the midline of the CNS, since the pattern for cuticle, segmentation, and muscles are normal. The normal axon projection of the ventral unpaired medial neurons (VUMs) is particularly interesting because the VUM cell bodies are located at the midline and extend growth cones that bifurcate and project away from the midline and toward the intersegmental nerve root. The fact that this happens in a relatively normal fashion in comm mutants suggests that there is no physical barrier preventing growth cones from extending near the midline. Later in embryogenesis, in the absence of commissural axon pathways and their surrounding nonneuronal cells holding the two sides of the CNS together, the CNS starts to unzip as it splits ...
Developing motoneurons in zebrafish embryos follow a stereotyped sequence of axonal outgrowth and accurately project their axons to cell-specific target muscles. During axonal pathfinding, an identified motoneuron pioneers the peripheral motor pathway. Growth cones of later motoneurons interact with the pioneer via contact, coupling, and axonal fasciculation. In spite of these interactions, ablation of the pioneer motoneuron does not affect the ability of other identified motoneurons to select the pathways that lead to appropriate target muscles. We conclude that interactions between these cells during pathfinding are not required for accurate pathway selection ...
Precise spatiotemporal control of axon guidance factor expression is a prerequisite for formation of functional neuronal connections. Although Netrin/Dcc- and Robo/Slit-mediated attractive and repulsive guidance of commissural axons have been extensively studied, little is known about mechanisms controlling mediolateral positioning of longitudinal axons in vertebrates. Here, we use a genetic approach in zebrafish embryos to study pathfinding mechanisms of dopaminergic and neuroendocrine longitudinal axons projecting from the hypothalamus into hindbrain and spinal cord. The transcription factors Sim1a and Arnt2 contribute to differentiation of a defined population of dopaminergic and neuroendocrine neurons. We show that both factors also control aspects of axon guidance: Sim1a or Arnt2 depletion results in displacement of hypothalamo-spinal longitudinal axons towards the midline. This phenotype is suppressed in robo3 guidance receptor mutant embryos. In the absence of Sim1a and Arnt2, expression ...
This study will use two-photon cellular imaging in an animal model of human multiple sclerosis (MS) to determine how neural-immune interactions may damage the nerve cells communication cables (axons) to produce disabling cognitive and motor disabilities. MS afflicts about 400,000 people in this country. It is an "autoimmune" disease in which the bodys immune cells mistake as foreign and attack some tissues in the brain and especially in the spinal cord (central nervous system, CNS). MS specifically targets a nerve cells axon and the myelin sheath that covers it. Axons carry nerve cell messages from one cell to another. Just how immune cells inflict damage to axons, however, is not yet known. The investigators hypothesize that "innate" immune cells, the bodys first line of defense, ordinarily help maintain the equilibrium of axons. But in autoimmune inflammation, they turn deadly and fatally injure axons. Since it is not currently feasible to image nerve-immune cell interactions in MS ...
This study will use two-photon cellular imaging in an animal model of human multiple sclerosis (MS) to determine how neural-immune interactions may damage the nerve cells communication cables (axons) to produce disabling cognitive and motor disabilities. MS afflicts about 400,000 people in this country. It is an "autoimmune" disease in which the bodys immune cells mistake as foreign and attack some tissues in the brain and especially in the spinal cord (central nervous system, CNS). MS specifically targets a nerve cells axon and the myelin sheath that covers it. Axons carry nerve cell messages from one cell to another. Just how immune cells inflict damage to axons, however, is not yet known. The investigators hypothesize that "innate" immune cells, the bodys first line of defense, ordinarily help maintain the equilibrium of axons. But in autoimmune inflammation, they turn deadly and fatally injure axons. Since it is not currently feasible to image nerve-immune cell interactions in MS ...
Topographical maps of neuronal connectivity occur in various brain regions. RGC axons have been shown to substantially overshoot their appropriate TZs along the AP axis of the optic tectum/SC during the development of the visual system in chicks and rodents. RGC axons from a given DV location are also broadly distributed along the DV (or mediolateral) tectal axis with a peak in axon density around the proper DV location of the TZ (Simon and OLeary, 1992a, 1992b, 1992c; Hindges et al., 2002). Topographically appropriate connections are then established by selective branching formed along the axon shaft with a bias at the AP location of their future TZ (Simon and OLeary, 1992a; Yates et al., 2001) and preferential extension toward the TZ along the DV axis (Nakamura and OLeary, 1989; Hindges et al., 2002; McLaughlin et al., 2003a). Thus, the target position-specific branching of RGC axons on the tectum is essential to establish a topographic retinotectal map. However, the molecular mechanisms ...
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They are caused by gene mutations that happen in abnormalities in the synthesis or catabolism of proteins, carbohydrates, or fats. The DRG contain pseudounipolar sensory neurons В- so called because they furnish arise to a individual axon that bifurcates, with one involvement projecting to the boundary and the other projecting to the dorsal horn of the spinal cord. Carrots check beta-carotene and former carotenoids cheap 0.18mg alesse with mastercard birth control lawsuit. Furthermore, uncountable of the ocular tissues and fluids collected in bioanalytical studies are present in such low amount or substance that reanalysis may be unaccommodating or unachievable, depending on the assay approach utilized. A Ladd returns is performed, during which the intestine is straightened out and bands contributing to the misalignment are divided. Heart disease and the incendiary activity dapoxetine 30mg online erectile dysfunction medication non prescription. The use of such instruments to right off the bat ...
Its not as rear as you make it out. Its quite common in SMA and SBMA and some muscular disorders to fasciculate well in advance of weakness or EMG changes. Ive know people that Ive talked with that twitched in their teens only later to be diagnosed with ALS, in-approrpriately, then diagnosis changed to another MND 30 years later. I may be one of them. Ive yet to show changes but Ive been told even after 20 years, Im not out of woods. Not by Dr. Google...or vet....etc. Ive had every test you can imagine, all negative, but still Im a very interesting subject because I fasciculate and have an elevated CPK for 20+ years. Nothing sinister on EMG. But I still see a neurologist. They want to run tests that my insurance company wont pay for....I wont do it unless my Son or Daughter show changes...Lately, my son started to fasciculate and his hands and feet are cramping..might be time to do more tests ...
Yuanyuan (Kevin) Liu has been awarded an American Heart Association Predoctoral Fellowship for his research. Yuanyuan is a graduate student in Biological Sciences in Professor Ben Szaros lab. The funding is for 2 years with a $20,000/yr stipend. The title of his award is: "Studies of an RNA binding protein and its mRNA targets during central nervous system axon regeneration." Of 115 proposals received, Yuanyuans was among the top 6 percent. More specific details about Yuanyuans study may be found below. After a stroke, patients frequently recover only partially due to the disruption of connections between neurons. In the human brain, axons which mediate these connections, generally fail to regenerate beyond the lesion site. In contrast, injured central nervous system neurons in lower vertebrates, such as the frog, can often fully regenerate. Yuanyuan Liu is using the regenerating optic nerve of the frog Xenopus laevis as a model system to study the mechanisms of successful central nervous ...
Nitric oxide gets neurons together. And it seems to do it backward. Work by Nikonenko et al. suggests that a protein called PSD-95 prompts nitric oxide release from postsynaptic dendritic spines, prompting nearby presynaptic ...
Hi there, Currently, when I use maven to build the project I have this problem. I have 2 projects: desk_post and desk_post_test (required desk_post) When I run for desk_post -> mvn clean install -> successful -> created: desk_post-1.00.08.00-SNAPSHOT.iar -> the resources folder alread...
SCOTTSDALE, Ariz., Dec. 1, 2016 /PRNewswire/ -- New Axon Signal Magazine Connects TASER Smart Weapons To Wearable Cameras. The Signal Performance Power...
New research sheds light on the molecular mechanisms underlying axon g...A group led by Michael Hengartner from the University of Zurich in Sw...Hengartner and colleagues then show that UNC-69 physically interacts w...It is known that UNC-76 binds to molecular motor proteins called kin...The short coiled-coil domain-containing protein UNC-69 cooperates with...,Newly,identified,protein,complex,sheds,light,on,axon,growth,mechanism,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
The computational model of in vivo sharp-wave ripples with place cell replay. Excitatory post-synaptic potentials at dendrites gate antidromic spikes arriving from the axonal collateral, and thus determine when the soma and the main axon fire. The model allows synchronous replay of pyramidal cells during sharp-wave ripple event, and the replay is possible in both forward and reverse directions ...
Principal Investigator:MASU Masayuki, Project Period (FY):2010-04-01 - 2015-03-31, Research Category:Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Project Area:Neural Diversity and Neocortical Organization
The cerebral cortex is essential for all sorts of processing of sense data and motor control. It is where the reasoning and cognition specific to humans (and, to a lesser degree, some other animals) takes place, and is the seat of planning and language, volitional behavior and conscious perceptions, thinking and memory. It is the command center where input sensory information is translated into output motor control. In evolutionary terms, it is the most recently developed part of our brains and has taken over or added to function of older structures.. Its unique and fairly uniform structure (sometimes termed "canonical") allows for great plasticity in functioning. It consists of layers1)Six, in the striate cortex.. of gray matter (neuron cells, dendrites and synapses) on the outside (distally) and white matter (axons) beneath, although the difference in colors is less pronounced than those terms may imply. It consists of two lateral hemispheres joined by a bundle of axonal connections, the ...
There is accumulating evidence that RelA is crucial for axon formation during embryonic neural development (Gavaldà et al., 2009). In cervical superficial ganglia, enhanced site-specific Ser536 phosphorylation of RelA in the presence of p50 impairs increases in neurite length and complexity (Gutierrez et al., 2008), whereas RelA suppression by overexpression of either p50 or a dominant-negative IκBα super-repressor in newborn hippocampal neurons results in complete growth arrest (Imielski et al., 2012). It has been suggested that modification of both IκBα and activated RelA determines a functional switch from growth inhibition to growth promotion (Gavaldà et al., 2009; Gutierrez et al., 2008). Moreover, as recently exemplified for hippocampal neurogenesis, the balance between transactivation-competent and -incompetent NF-κB subunits might also be crucial for axogenesis (Imielski et al., 2012). However, such previous experiments were based on in vitro analysis of premature PNS and newborn ...
GO:0048846. The long distance growth of a single cell process, that is involved in the migration of an axon growth cone, where the migration is directed to a specific target site by a combination of attractive and repulsive cues. ...
Slit1 triggers Netrin-1 repulsion for hippocampal neurons on PLL-coated substrate. (A) Last brighfield images of typical growing axons on PLL-coated microwells.
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THIS GUIDE IS JUST FOR THE USA VARIANT OF THE ZTE AXON 7 ( A2017U ) DO NOT ATTEMPT THIS ON ANY OTHER AXON 7 DEVICE - YOUVE BEEN WARNED -
The purpose of this book is to provide a straightforward but thorough introduction to accounting and finance for executives and managers who are studying these subjects, formally, for the first time. It is an entry-level text to be used before moving on to more advanced material. A high degree of practicality and relevance are introduced with a strong real world flavour supported by examples from leading international companies. The glossary of terms is designed to be as comprehensive as possible so that readers can obtain clear guidance at a time when they most need it.... ...
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We show that the perceptual experience of retinal implant users can be accurately predicted using a computational model that simulates each individual patients retinal ganglion axon pathways ...
During the GEF-6 replenishment, the focal area strategies were designed to meet specific measured by key indicators. After one year of GEF-6 programming in which 20.4 percent of GEF-6 resources were programmed, the planned expected results among approved projects in five of the ten target areas were already close to or beyond the 50 percent mark in the programming of the overall planned expected results of the target area. It should be noted though, that these data are based on expected, not actual results, which will only materialize as implementation progresses.. ...
REGULATION OF AXONAL DEVELOPMENT BY THE cGMP SIGNALING PATHWAY By Zhen Zhao A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirement for the Degree DOCTOR OF PHILOSOPHY (NEUROSCIENCE) December 2009 Copyright 2009 Zhen Zhao ii Acknowledgements I would like to express my gratitude to all those who assisted me to complete my work and this thesis. I want to thank University of Southern California, Neuroscience Graduate Program and Zilkha Neurogenic Institute for giving me the opportunity to pursue my doctoral degree. I am deeply indebted to my supervisor Prof. Dr. Le Ma. It was his guidance, encouragement, suggestions and full support that made this work possible. I also have to thank my committee members, Dr. Samantha Buttler, Dr. James Knowles, Dr. Emily Liman, Dr. David Mckemy, Dr. Zuo-zhong Wang and Dr. Qilong Ying for their valuable help, and Dr. Li Zhangs lab, Dr. Jonah Chan and Dr, Zuo-zhong Wangs lab for ...
REGULATION OF AXONAL DEVELOPMENT BY THE cGMP SIGNALING PATHWAY By Zhen Zhao A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirement for the Degree DOCTOR OF PHILOSOPHY (NEUROSCIENCE) December 2009 Copyright 2009 Zhen Zhao ii Acknowledgements I would like to express my gratitude to all those who assisted me to complete my work and this thesis. I want to thank University of Southern California, Neuroscience Graduate Program and Zilkha Neurogenic Institute for giving me the opportunity to pursue my doctoral degree. I am deeply indebted to my supervisor Prof. Dr. Le Ma. It was his guidance, encouragement, suggestions and full support that made this work possible. I also have to thank my committee members, Dr. Samantha Buttler, Dr. James Knowles, Dr. Emily Liman, Dr. David Mckemy, Dr. Zuo-zhong Wang and Dr. Qilong Ying for their valuable help, and Dr. Li Zhangs lab, Dr. Jonah Chan and Dr, Zuo-zhong Wangs lab for ...
Immature motoneurons are highly susceptible to degeneration following axon injury. The response of perineuronal glia to axon injury may significantly influence neuronal survival and axon regeneration. We have examined the central reactions to neonatal facial nerve transection with emphasis on the expression of complement component C3 (C3) and the multifunctional apolipoprotein J (ApoJ). Axotomy was performed on one-day-old rats. Animals were perfused from eight hours to two weeks after the lesion. The astroglial marker, glial fibrillary acidic protein (GFAP) was increased from one day and the microglial marker OX-42 from two days after injury. ApoJ immunoreactivity was increased in axotomized neuronal perikarya and astroglial cells from one day postaxotomy, but no C3 immunoreactive profiles were found at any postoperative survival time. Cell proliferation as judged by bromodeoxyuridine labeling and immunoreactivity for the cyclin Ki-67 antigen (antibody MIB5) occurred only at two days after ...
In contrast to the central nervous system (CNS) nerve fibers do regenerate in the peripheral nervous system (PNS) although in a clinically unsatisfying manner. A major problem is excessive sprouting of regenerating axons which results in aberrant reinnervation of target tissue and impaired functional recovery. In the CNS, the reticulon protein Nogo-A has been identified as a prominent oligodendrocyte expressed inhibitor of long-distance growth of regenerating axons. We show here that the related isoform Nogo-B is abundantly expressed in Schwann cells in the PNS. Other than Nogo-A in oligodendrocytes, Nogo-B does not localize to the myelin sheath but is detected in the ER and the plasma membrane of Schwann cells. Adult sensory neurons that are cultured on nogo-a/b deficient Schwann cells form significantly fewer axonal branches versus those on wildtype Schwann cells, while their maximal axonal extension is unaffected. We demonstrate that this effect of Nogo-B on neuronal morphology is restricted to
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We recently noted, in performing a metabolic characterization of mice deleted for LKB1 in the endocrine pancreas and a restricted set of CNS neurons using a RIP2-Cre transgene (Sun et al., 2010b), that older animals became paralyzed. The principal aim of the present study was thus to dissect the pathology behind this change and, in doing so, to determine the role of LKB1 in regulating neuronal polarity and survival in the CNS in vivo.. Although mice null for LKB1 throughout the body die before E11.5, the use of an Emx1-Cre deleter strain to allow deletion in pyramidal neuron progenitors demonstrated that LKB1 is required for the polarization of cultured neurons from the neonatal hippocampus and cortex (Barnes et al., 2007; Shelly et al., 2007). We therefore reasoned that LKB1 might play a similar role in axon development and, importantly, in signal transmission along the spinal cord. Given the crucial role of the spinal cord for the normal control of motor function, we further reasoned that ...
This allowed us to systematically investigate how metabolic cost depends on factors such as axonal geometry and ion channel densities. E.g comparing myelinated and unmyelinated axons with the same axon diameter of 1µm (fibre diameter including myelin sheath was 3.7 µm) we find the following: single APs at a myelinated axons Node of Ranvier have a metabolic cost of 3.5 pmol/cm² ATP per unit membrane area. This is approximately 7 times the amount per AP in hippocampal mossy fibre (0.53 pmol/cm2;[2]) but less than leaky squid axons (5 pmol/cm2). However, Node of Ranvier cover only 0.33% in our myelinated axon. The internodal regions contain hardly any Na+ channels, but a low density of K+ channels (3 µm-2) along internodes, and higher densities at the paranode (80 µm-2). We estimate overall energy consumption based on Na currents at the Node and K along a segment comprising half the internodal fibre on both sides of a node. This yields an AP cost per myelinated axon segment of 0.05 pmol/cm2 ...
Histology in DAI. A number of histological techniques are available to appreciate sequential pathological changes in axons in diffuse axonal injury. These are primarily aimed at shortening the duration at which the axonal changes are seen and to put them in context to various traumatic and non traumatic conditions so as to differentiate the causative mechanism. Axonal swellings or retraction balls, representing transected axons, are the histological hallmark of axonal injury but are usually not visible before 24 to 36 hours by routine H & E staining or with a myelin stain like Luxol fast blue [2]. Silver staining method can reliably demonstrate axonal swellings within 12 to 18 hours [27]. The method has been found to be more sensitive and reliable as compare to H & E staining. However diffuse staining of axons by silver stains may occasionally make differentiation of injured and irregular axons difficult thereby limiting their practical utility [28]. Injuries to the axons may be detected even ...
Authors: Carter, Deborah A. , Lisney, S.J.W. Article Type: Research Article Abstract: Counts of myelinated and unmyelinated axon profiles have been made from normal, uninjured rat sural nerves and from nerves injured 6 months earlier in one of two ways. In one group of rats the nerve was simply cut and left to regenerate, leading to the development of a neuroma in continuity, while in the second group the nerve was cut but then ligated as well to prevent regeneration; this led to stump neuroma formation. After nerve transection and regeneration, with subsequent formation of a neuroma in continuity, there was no change in the number of myelinated axon profiles found 25 …mm proximal to the old injury site when compared with control, but there was an 18% reduction (P , 0.05) in the number of unmyelinated axon profiles. Immediately proximal to the injury site the picture was similar, with there still being the same number of myelinated axon profiles as in control material but here the reduction in ...
Many guidance receptors are proteolytically cleaved by membrane-associated metalloproteases of the ADAM family, leading to the shedding of their ectodomains. Ectodomain shedding is crucial for receptor signaling and function, but how this process is controlled in neurons remains poorly understood. Here, we show that the transmembrane protein Lrig2 negatively regulates ... read more ADAM-mediated guidance receptor proteolysis in neurons. Lrig2 binds Neogenin, a receptor for repulsive guidance molecules (RGMs), and prevents premature Neogenin shedding by ADAM17 (TACE). RGMa reduces Lrig2-Neogenin interactions, providing ADAM17 access to Neogenin and allowing this protease to induce ectodomain shedding. Regulation of ADAM17-mediated Neogenin cleavage by Lrig2 is required for neurite growth inhibition by RGMa in vitro and for cortical neuron migration in vivo. Furthermore, knockdown of Lrig2 significantly improves CNS axon regeneration. Together, our data identify a unique ligand-gated mechanism to ...
However, new insights into the basic properties of fast axonal transport are beginning to illuminate the roles that it may play during axonal growth. Although fast axonal transport is often used to refer solely to the movement of materials at the fastest orthograde rate, there is good reason for including in fast axonal transport the translocation of membranous organelles of all types in both directions (Lasek and Brady, 1982). The original descriptions of fast axonal transport (for example, see Lasek, 1967; Dahlstrom and Haggendahl, 1967; Grafstein, 1967) focused on the fastest moving elements leaving the cell bodies and defined this as fast axonal transport. I I FIGURE 3. Various responses of the facial nerve cell bodies following different types of axonal injuries in different animal species. , 1982). Biochemical changes in the nerve cell body occur after the injection of botulinum toxin into the area of neuromuscular junction. Watson (1974) suggested that since botulinum toxin causes a block ...
During development, the axons of retinal ganglion cell (RGC) neurons must decide whether to cross or avoid the midline at the optic chiasm to project to targets on both sides of the brain. By combining genetic analyses with in vitro assays, we show that neuropilin 1 (NRP1) promotes contralateral RGC projection in mammals. Unexpectedly, the NRP1 ligand involved is not an axon guidance cue of the class 3 semaphorin family, but VEGF164, the neuropilin-binding isoform of the classical vascular growth factor VEGF-A. VEGF164 is expressed at the chiasm midline and is required for normal contralateral growth in vivo. In outgrowth and growth cone turning assays, VEGF164 acts directly on NRP1-expressing contralateral RGCs to provide growth-promoting and chemoattractive signals. These findings have identified a permissive midline signal for axons at the chiasm midline and provide in vivo evidence that VEGF-A is an essential axon guidance cue.
Individual neurons in vertebrates are typically highly branched with a complex morphology of their processes (axons and dendrites). In C. elegans almost all neuronal processes are unbranched and extend in a stereotpical fashion. The example in Figure 3 shows a pair of sensory neurons (ASH) with cell bodies located in head ganglia. The two ASH neurons are chemosensory neurons. A single process, the dendrite, extends from the cell body towards the tip of the nose. A second process, the axon, grows first towards the ventral cord through the amphid commissure. It then turns anteriorly and loops in a halfcircle around the pharynx (not visible) within a large axon bundle - the nerve ring (note: the processes in the ventral cord in the figure belong to a second pair of neurons (PVQ) with cell bodies in the tail). The nerve ring is a horseshoe-shaped axon bundle containing neuronal processes of sensory and interneurons which form connections (synapses) as they run next to each other.. The invariant ...
foxP2, a forkhead-domain transcription factor, is critical for speech and language development in humans, but its role in the establishment of CNS connectivity is unclear. While in vitro studies have identified axon guidance molecules as targets of foxP2 regulation, and cell culture assays suggest a role for foxP2 in neurite outgrowth, in vivo studies have been lacking regarding a role for foxP2 in axon pathfinding. We used a modified zinc finger nuclease methodology to generate mutations in the zebrafish foxP2 gene. Using PCR-based high resolution melt curve analysis (HRMA) of G0 founder animals, we screened and identified three mutants carrying nonsense mutations in the 2nd coding exon: a 17 base-pair (bp) deletion, an 8bp deletion, and a 4bp insertion. Sequence analysis of cDNA confirmed that these were frameshift mutations with predicted early protein truncations. Homozygous mutant fish were viable and fertile, with unchanged body morphology, and no apparent differences in CNS apoptosis,
In this simulation action potential initiation, action potential properties and the role of axon initial segment Na+ channels are investigated in a realistic model of a layer 5 pyramidal neuron axon initial segment. The main Na+ channel properties were constrained by experimental data and the axon initial segment was reconstructed. Model parameters were constrained by direct recordings at the axon initial segment ...
Cranial nerves innervate head muscles in a well-characterized and highly conserved pattern. Identification of genes responsible for human congenital disorders of these nerves, combined with the analysis of their role in axonal development in animal models, has advanced understanding of how neuromuscular connectivity is established. Here, we focus on the ocular motor system, as an instructive example of the success of this approach in unravelling the aetiology of human strabismus. The discovery that ocular motility disorders can arise from mutations in transcription factors, including HoxA1, HoxB1, MafB, Phox2A, and Sall4, has revealed gene regulatory networks that pattern the brainstem and/or govern the differentiation of cranial motor neurons. Mutations in genes involved in axon growth and guidance disrupt specific stages of the extension and pathfinding of ocular motor nerves, and have been implicated in human strabismus. These genes encompass varied classes of molecule, from receptor ...
Vertebrate branchial nerves, i.e., the Vth, VIIth, IXth, and Xth cranial nerves, have neural crest-derived and placode-derived sensory neurons in their proximal and distal ganglia, respectively [18]. These nerves also have motor neurons, the cell bodies of which lie in the ventral hindbrain; and their axons project to the branchial arches through proximal and distal ganglia during development [39]. The sensory ganglia of these nerves are known to be weakly chemoattractive for motor neurons, as shown in co-culture experiments [40]. It is known that placode-derived neurons differentiate earlier than neural crest-derived ones [41, 42] and that in embryos where the placodes have been removed, the axonal projection pattern of proximal ganglion neurons to the periphery is defective [43]. These findings suggest that proper developmental regulation of the placode-derived neurons should be required for all 3 types of branchial nerve neurons, i.e., the 2 sensory types (neural crest-derived and ...
Normal brain function depends on the development of appropriate patterns of neural connections. A critical role in guiding axons to their targets during neural development is played by neuronal growth cones. These have a complex and rapidly changing morphology; however, a quantitative understanding of this morphology, its dynamics and how these are related to growth cone movement, is lacking. Here we use eigenshape analysis (principal components analysis in shape space) to uncover the set of five to six basic shape modes that capture the most variance in growth cone form. By analysing how the projections of growth cones onto these principal modes evolve in time, we found that growth cone shape oscillates with a mean period of 30 min. The variability of oscillation periods and strengths between different growth cones was correlated with their forward movement, such that growth cones with strong, fast shape oscillations tended to extend faster. A simple computational model of growth cone shape dynamics
Inactivation of the sodium current in squid giant axons by hydrocarbons.: The voltage dependence of the steady state inactivation parameter (h infinity) of the
The aim of this study was to evaluate changes in sensory axonal excitability in the distal nerve in patients with cervical radiculopathy. The patients were classified by the findings of cervical MRI into two subgroups: 22 patients with C6/7 roo
www.MOLUNA.de New Aspects of Axonal Structure and Function [4212751] - A summary of recent findings covering the morphological, physiological, developmental, computational and pathophysiological aspects of axons, this volume covers new findings concerning axonal structure and functions and assesses their implications.nAxons are neuronal output elements and are responsible for the transfer and processing of signals from one neuron to another, even
Abstract: Axotomy-induced degradation of retinal ganglion cells (RGC) can be delayed if the destructive features of activated Microglial cells are pharmacologically neutralized, and prevented if the axons are permitted to regrow into transplanted autologous peripheral nerve (PN) pieces. Axotomized central nervous system neurons, whose regenerating axons are guided to their natural target areas in the brain with the aid of PN grafts, are capable of establishing synaptic contacts with normal morphological and electrophysiological properties. This study was undertaken to 1) morphometrically characterize and classify the regenerating rat RGC, 2) examine target-dependent effects on survival of subsets of neurons, and 3) investigate whether reconnected neurons are capable of restoring visual functions. In analogy to the normal rat retina, as a first step, the retrogradely labeled, regenerating RGC were categorized into five classes which are morphologically distinct and reminiscent of normal RGC ...
Adenomatous polyposis coli (APC) is a microtubule plus-end scaffolding protein important in biology and disease. APC is implicated in RNA localization, although the mechanisms and functional significance remain unclear. We show APC is an RNA-binding protein and identify an RNA interactome by HITS-CLIP. Targets were highly enriched for APC-related functions, including microtubule organization, cell motility, cancer, and neurologic disease. Among the targets is β2B-tubulin, known to be required in human neuron and axon migration. We show β2B-tubulin is synthesized in axons and localizes preferentially to dynamic microtubules in the growth cone periphery. APC binds the β2B-tubulin 3 UTR; experiments interfering with this interaction reduced β2B-tubulin mRNA axonal localization and expression, depleted dynamic microtubules and the growth cone periphery, and impaired neuron migration. These results identify APC as a platform binding functionally related protein and RNA networks, and suggest a ...
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Department of Life Science and Technology home page - How developing visual system axons stay in the correct layer - Department of Life Science and Technology, School of Life Science and Technology, Tokyo Institute of Technology.Little is known about how axons in the developing visual system stabilize their connections upon rea...
Purchasing goods from distant locations introduces a significant lag between when a product is shipped and when it arrives. This is problematic for firms facing volatile demand, who must place orders before knowing the resolution of demand uncertainty. We provide a model in which airplanes bring producers and consumers together in time. Fast transport allows firms to respond quickly to favorable demand realizations and to limit the risk of unprofitably large quantities during low demand periods. Fast transport thus provides firms with a real option to smooth demand volatility. The model predicts that the likelihood and extent to which firms employ air shipments is increasing in the volatility of demand they face, decreasing in the air premium they must pay, and increasing in the contemporaneous realization of demand. We confirm all three conjectures using detailed US import data. We provide simple calculations of the option value associated with fast transport and relate it to variation in goods ...
Wallerian degeneration (Fig. 2 A, left) is undoubtedly the most thoroughly investigated form of axon loss-and indeed, ongoing research is revealing the molecular pathways that result in the removal of severed axon segments. The starting point for this mechanistic deconstruction of Wallerian axon dismantling has been the serendipitous identification of a spontaneous mouse mutant with profoundly delayed Wallerian degeneration (WLDS [Wallerian degeneration slow]; Lunn et al., 1989). Molecular genetic analysis of this mutant has resulted in the surprising identification of enzymes of the NAD biosynthetic pathway as central players in axon degeneration (Coleman et al., 1998; Conforti et al., 2000), even though the details of the underlying molecular mechanisms that actually result in axon fragmentation remain to be elucidated. Importantly, the phylogenetic conservation of WLDS sensitivity has allowed identification of Wallerian-like degeneration events in "screenable" organisms, such as Drosophila ...
Calbindin immunohistochemistry on 100 µm cerebellar neocortex sections, 100x. (A) Normal control brain with thin visible axonal profiles. (B) Three torpedoes (arrow heads), two of which are on axons with recurrent collaterals (carets). Several thickened axonal profiles are shown (short arrows). (C) Terminal axonal sprouting (thick arrow). (D) Arciform axon profile; profile is also thickened. (E) Torpedoes (arrow heads) with axonal recurrent collaterals (carets) and axonal branching (long arrows and inset). (F) A visible portion of the recurrent collateral plexus at the Purkinje cell layer (boxed). (G) Thickened axonal profiles (short arrows). ...
Calbindin immunohistochemistry on 100 µm cerebellar neocortex sections, 100x. (A) Normal control brain with thin visible axonal profiles. (B) Three torpedoes (arrow heads), two of which are on axons with recurrent collaterals (carets). Several thickened axonal profiles are shown (short arrows). (C) Terminal axonal sprouting (thick arrow). (D) Arciform axon profile; profile is also thickened. (E) Torpedoes (arrow heads) with axonal recurrent collaterals (carets) and axonal branching (long arrows and inset). (F) A visible portion of the recurrent collateral plexus at the Purkinje cell layer (boxed). (G) Thickened axonal profiles (short arrows). ...
... arborize arborize ar·bo·rize (ärbə-rīz) v. ar·bo·rized, ar·bo·riz·ing, ar·bo·riz·es To ramify. Historical Examples Each also gives off a number of finer
The study of spinal nerve trajectories in higher vertebrate embryos has revealed an inherent polarity within somites along the antero-posterior axis, and provides a simple system in which to study the factors that influence axon pathfinding. We argue that the orientation of spinal axons is determined by the simultaneous operation of two distinct guidance mechanisms, contact repulsion and chemorepulsion. Motor and sensory axons traverse the anterior half of each somite because they are excluded by contact repulsion from the posterior half-somite, and the molecular nature of several candidate contact repellents is reviewed. In contrast, we find that the dorsoventral trajectory of primary sensory axons is oriented by diffusible repellents originating from the notochord medially and dermamyotome laterally. In this system, therefore, repulsion by surrounding tissues (surround-repulsion) is the main force directing axon growth in three dimensions.
Localization of synaptotagmin, a Ca,sup,2+,/sup,-binding protein associated with synaptic vesicles, in regenerating axons was investigated by immunocytochemistry in the injured rat sciatic nerves. The early regenerating axonal sprouts emanating from nodes of Ranvier exhibited synaptotagmin immunoreactivity on vesicles, vacuoles and surface plasma membranes. In the well-developed regenerating sprouts extending through the space between Schwann cell basal lamina and myelin sheath of the parent axon, the growing tips, ,i,i.e,/i,., typical growth cones, exhibited an intense immunoreaction on vesicles, vacuoles and surface plasma membranes, while the stem regions where the sprouts were continuous with the parent axon exhibited almost no immunoreaction on any organelles including plasma membranes. These findings suggest that synaptotagmin-immunoreactive vesicles and vacuoles might be utilized for the supply of membrane components to the surface plasma membrane in the growth cone. Synaptotagmin which ...
Dent, PhD, E. W. Branch Management: Mechanisms of Axon Branching in the Developing Vertebrate CNS. Kalil K, Dent EW. (2014) Branch management: mechanisms of axon branching in the developing vertebrate CNS. Nature Reviews Neuroscience. 15(1):7-18. …
Sigma-Aldrich offers abstracts and full-text articles by [Anke A Dijkstra, Angela Ingrassia, Renee X de Menezes, Ronald E van Kesteren, Annemieke J M Rozemuller, Peter Heutink, Wilma D J van de Berg].
Axon Diameter Distributions (ADDs) change during brain development and are altered in several brain pathologies. Mapping ADDs non-invasively using dMRI could provide a useful biomarker, but existing methods are either parametric, orientation dependent, surmmarize the whole ADD as a single measure or use non-standard protocols. We propose to estimate the ADD from an orientation-invariant PGSE protocol optimized for axon diameter sensitivity, using a discrete linear model with smoothness and sparsity regularization. To our knowledge, we are the first to report orientationally invarant ADD estimates from dMRI data.. Keywords: non-parametric ADD mapping ; microstructure ; diffusion MRI. ...
The distribution of infused tritiated norepinephrine (NE-3H) in small mesenteric arteries and intestinal arterioles in rats was investigated with electron microscopic radioautography. Silver grains, indicating the presence of the tritium label on the sections, were found lying mainly over axon bundles, but some were present over collagen and smooth muscle cells. Axons with the highest concentrations of silver grains had been sectioned at points where they were naked of Schwann cell sheath, were dilated into varicosities, and contained small granular vesicles. This finding was taken as confirmatory circumstantial evidence that the small granular vesicles were the sites of uptake and storage of NE. The short interval between the start of infusion and the fixation of the tissue appeared to rule out any process other than a direct uptake of NE by the peripheral axons. If axonal sites of uptake of NE-3H correspond to sites of release of NE, then the evidence suggests that such sites of release are ...
Axon Growth and Regeneration: Methods and Protocols brings together a diverse set of techniques for the study of the mechanisms underlying central nervous system axon growth, consequently providing a resource that will aid in the development of repair strategies. After an introductory section, this
Radial glial cell-neuron interaction directs axon formation at the opposite side of the neuron from the contact siteRadial glial cell-neuron interaction directs axon formation at the opposite side of the neuron from the contact site ...
Axonal excitability testing provides in vivo assessment of axonal ion channel function and membrane potential. Excitability techniques have provided insights into the pathophysiological mechanisms und
The largest neurons, which are mostly motor neurons, differentiate first. Sensory and small neurons, and most of the glial cells, appear later, up to the time of birth. Newly formed neurons may migrate extensively through regions of previously formed neurons. When glial cells appear, they can act as a framework that guides growing neurons to the correct target areas. Because the axonal process of a neuron may begin growing toward its target during migration, nerve processes in the adult brain are often curved rather than straight. ...
The long length of axons makes them critically dependent on intracellular transport for their growth and survival. This movement is called axonal transport. Cargoes originating from the cell body move out towards the axon tip and cargoes originating in the axon or at the axon tip move back towards the cell body. The outbound movement is known as anterograde transport and it includes cargoes required for the growth, maintenance and plasticity of axons and presynaptic terminals. The inbound movement is called retrograde transport and it includes cargoes returning to the cell body for recycling or degradation, as well as cargoes that relay signals back to the cell body to modulate gene expression in response to the local environment.. Though axonal transport has a special name, it is not fundamentally different from the pathways of intracellular traffic found in other parts of nerve cells or in other cells. However, it is remarkable for its scale. For example, there are axons in our bodies that ...
There are striking differences in the ability of vertebrates to repair axonal connections. Mammals cannot regenerate CNS axons efficiently, resulting in permanent loss of function after injury. In contrast, non-mammalian species (particularly fish and amphibians) are able to functionally restore distrupted CNS axon connections. Against this background, my work is focused on the following aspects:. ...
The effect of 6-hydroxydopamine (6-OHDA) on the ultrastructure, fluorescent histochemistry, electrophysiology and pharmacology of the mouse and rat vas deferens has been examined during the first 24 hours after single intravenous injections. During the first hour there was a marked increase in the granulation of the intra-axonal vesicles, spontaneous contractions occurred, and there was an increase in the frequency of spontaneous junction potentials. These results indicate the displacement, by 6-OHDA, of discrete packets of noradrenaline from intra-axonal stores. By 4 to 6 hours, there was a general decrease in the fluorescent intensity of adrenergic nerves. At 24 hours the fluorescent intensity of the nerves had returned to about normal, but there was a dose-dependent decrease in the number of nerves. The first sign of axon damage was seen at 1 to 2 hours, consisting of a general electron transparency of the axoplasm and a decrease in the number of axonal inclusions. Some of the axons recover ...
Growing neurites, which can be quite long and travel far in the body, advance as the growth cone at the tip of each one extends filopodia to drag it along an extracellular matrix of fibrous proteins. The axons tend to grow in groups of neurites stuck together7)"Axons which stick together grow together"?. , each group dragged along step-by-step by one axon called the pioneer axon. The growth cone is attracted or repelled by various chemical substances already released during embyronic development. The concentration gradients of such chemicals guide the axons to their destinations. Further detail on connections is furnished by molecular surface markers on target cells; these markers are recognized by specific growing axons.. This method of connecting neurons is as remarkable as it is necessary. There are not enough coding genes in the human genome to specify all the connections of the 10 billion cells in our brains. What is specified are the functions - chemicals, markers and growth factors - ...
J:190657 Cho JH, Kam JW, Cloutier JF, Slits and Robo-2 regulate the coalescence of subsets of olfactory sensory neuron axons within the ventral region of the olfactory bulb. Dev Biol. 2012 Nov 15;371(2):269-79 ...
In Drosophila, Netrins and their receptors DCC and Unc-5 are known to be important for proper axon guidance. However, Hiramoto et al. demonstrate that photoreceptors adopt a different mechanism of target guidance involving Netrin and Frazzled, a protein orthologous to DCC. Netrin transcripts and Netrin protein do not colocalize; Netrin protein localizes to the dorsolateral region, highly overlapping with the distribution of Frazzled. The specific localization of Frazzled depends on its cytoplasmic domain. The Drosophila pioneer neuron dMP2 requires proper localization of Netrin and Frazzled for its migration; however, the authors demonstrated that Frazzled does not act in a cell-autonomous manner (where Frazzled would act as a sensor for Netrin), but in fact, Frazzled acts as an attractant (with Netrin) to guide migrating neurons. Because the dMP2 neuron does not express Frazzled protein, this implies that another, uncharacterized receptor is expressed by dMP2 to bind Frazzled-captured Netrin ...
July 1, 2007. The Axon. An examination to gain understanding of the peripheral nervous system axon. by Jack Vander Beek. Part 1.. With this article we begin a series aimed at exploring a singularly unique and mostly overlooked part of vertebrate anatomy. This area is the domain of the regional nerve block and its characteristics determine the success or failure of your regional nerve block. This is also the region where conditions occasionally align to create the worst outcome of the regional nerve block, permanent nerve injury. It has no observable moving parts. It uses energy silently but efficiently. It is tolerant of most abuses but seems very slow to repair even the slightest damage. Its work is done on the molecular level and our understanding of this domain is crude and limited, but we impose on its hospitality everyday. We inject our drugs around it to purposefully stop it from doing its job, then sit back and expect it to clean up the mess and go back to business as usual, on our ...
Neurons consist of four elements, the soma, dendrite, axon and terminal. They work in concert as the input (soma and dendrite) and output (axon and terminal) parts of neuronal transmission. To function and maintain neuronal activity and metabolisms, proteins and organelles should be transported from soma to terminal via anterograde axonal transport, and also from terminal to soma via retrograde transport. By utilizing these transport systems, neural projection is traced by injecting tracers into local sites of interest. Furthermore, neurochemical properties, such as glutamatergic and GABAergic, can be determined by combining retrograde and anterograde tracing with fluorescent in situ hybridization and immunofluorescence.
Show moreSocial scientists regularly rely on population estimates when studying change in small areas over time. Census tract data in the United States are a prime example, as there are substantial shifts in tract boundaries from decade to decade. This study compares alternative estimates of the 2000 population living within 2010 tract boundaries to the Census Bureaus own retabulation. All methods of estimation are subject to error; this is the first study to directly quantify the error in alternative interpolation methods for U.S. census tracts. A simple areal weighting method closely approximates the estimates provided by one standard source (the Neighborhood Change Data Base), with some improvement provided by considering only area not covered by water. More information is used by the Longitudinal Tract Data Base (LTDB), which relies on a combination of areal and population interpolation as well as ancillary data about water-covered areas. Another set of estimates provided by the National ...
We offer these 14 PerfectWestern Containers in Compartmented/Sectional format (CLICK HERE) for membrane strips. These include containers for very thin strips (~0.6 cm wide) to thicker strips (5 cm wide), and as short as 7.3 cm to as long as 21.3 cm for various gel formats.. All containers are available in clear versions & most are also available in black for light-sensitive applications. Dimensions, Catalog numbers, and Recommended volumes are listed in the Specifications Tab on the product pages.. Note: We also have 12 Single-chamber containers for whole blots and 11 Single-chamber containers for membrane strips.. ...
To classify reliably cortical NPY neurons, used unsupervised clustering algorithms based on laminar location and electrophysiological and molecular properties. These classification schemes confirmed that NPY neurons are nearly exclusively GABAergic and are three main types (1) Neurogliaform-like neurons exhibiting a dense axonal arbor, were the most frequent and superficial, and substantially expressed the neuronal isoform of nitric oxide synthase. (2) Martinotti-like cells characterized by an ascending axon ramifying in layer I coexpressed somatostatin and were the most excitable type. (3) Among fast-spiking and parvalbumin-positive basket cells, NPY expression was correlated with pronounced spike latency ...
The axon is a fiber that extends from the cell body to the terminal endings. The axon is the main conducting unit of the neuron. It conveys electrical and neuron signals long distances that can vary form 0.1 mm to 2m. The longer the axon the faster the information is sent. Some axons split into branches that allow them to get information to different targets. Some axons are wrapped in a Myelin sheet which is made out of insulating membranes. It protects the axon and makes sure other axons dont interfere with one another. Also it helps to send information faster. Most neurons only have one axon. ...
Axonal transport plays a crucial role in neuronal morphogenesis, survival and function. Despite its importance, however, the molecular mechanisms of axonal transport remain mostly unknown because a simple and quantitative assay system for monitoring this cellular process has been lacking. In order to better characterize the mechanisms involved in axonal transport, we formulate a novel computer-assisted monitoring system of axonal transport. Potential uses of this system and implications for future studies will be discussed.
Free Sample - Hito CryoMyelinStain™ Kit, in a ready-to-use format and offers high quality, rapid staining of myelin/myelinated axons on frozen sections (mounted or floating), this kit offers a fast and reliable way to determine the extent of demyelination
The Salk researchers discovered that only a few proteins on the leading edge of a motor neurons axon - its outgoing electrical "wire" - and within the extracellular soup it travels through guide the nerve as it emerges from the spinal cord. These molecules can attract or repel the axon, depending on the long and winding path it must take to finally connect with its target muscle ...
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Cells are highly compartmented bodies. Or, you could say that many smaller bodies are highly compartmented in cells. The cell bodies are compartmented, yet they pass along their products to other bodies in the cells. Each body in a cell has a "job" to do. The job is to process chemicals in a highly ordered and efficient way, as in an assembly line. These processes are called biochemical pathways. The pathways differ from the conventional straightforward assembly line in that there are loops along the way. The loops are places where energy must come in to power the pathway along. The rules for the pathways are similar to your computer rules. Unless every dot, dash or comma is in absolutely the correct place, the system wont work. To make an extremely long story short, some of the nasty chemicals disrupt or block the pathways. It really does not matter where in the sequence of items the block comes; in a short time the entire pathway scrambles or shuts down. As more pathways shut down, it is not ...
Healthcare charities are facing a drop in donations due to #coronavirus in the coming months. If you are able, please support them! We sported our most stylish, splendid and silly hats for #WearAHatDay at our virtual Friday drinks with @madano to raise money for @braintumourrsch! pic.twitter.com/xJRGPmZnUs. ...
For the last 15 years, the proposed underlying mechanism for an axons diameter growth has focused on myelin-dependent modification of regions of neurofilaments that are located within the heavy and medium subunits. In a previous study, genetically removing the region of the medium subunit that is modified impaired growth and slowed nerve conduction. However, this did not directly test if the proposed modification was required as a much larger region was genetically removed. In the current study, researchers genetically altered the neurofilament medium subunit such that it could no longer be modified in response to myelination. Surprisingly, Garcia found that prevention of what was thought to be an extremely important modification did not affect axonal diameter ...
The Neurofilament L/M/H Antibody Sampler Kit offers flexibility for sampling and detection of neurofilaments under normal and pathophysiological conditions. This selection of antibodies allows visualization of neuronal axons, dendrites, and cell bodies depending on the clone utilized. Clone SMI 31 r
Researchers at University of California, San Diego School of Medicine report a previously unappreciated phenomenon in which the location of injury to a neurons communication wire in the spinal cord - the axon - determines whether the neuron simply stabilizes or attempts to regenerate. The study, published April 30 by Neuron, demonstrates how advances in live-imaging techniques are revealing new insights into the bodys ability to respond to spinal cord injuries.. While the body of a neuron is small, its axon can extend far up or down the spinal cord, which is about one and half feet long in humans. Along that distance, the axon branches out to make hundreds of connections with other cells, sending out signals that allow us to sense and respond to the world around us. Unless something happens to disrupt the axons reach, that is. Adult human axons in the brain and spinal cord are very limited in their ability to regenerate after injury - a hurdle that many researchers are trying to overcome in ...
Thalamocortical axons (TCAs) originate in dorsal thalamus, extend ventrally along the lateral thalamic surface, and as they approach hypothalamus make a lateral turn into ventral telencephalon. In vitro studies show that hypothalamus releases a chemorepellent for TCAs, and analyses of knockout mice indicate that Slit chemorepellents and their receptor Robo2 influence TCA pathfinding. We show that Slit chemorepellents are the hypothalamic chemorepellent and act through Robos to steer TCAs into ventral telencephalon. During TCA pathfinding, Slit1 and Slit2 are expressed in hypothalamus and ventral thalamus and Robo1 and Robo2 are expressed in dorsal thalamus. In collagen gel cocultures of dorsal thalamus and Slit2-expressing cells, axon number and length are decreased on the explant side facing Slit2-expressing cells, overall axon outgrowth is diminished, and axons turn away from the Slit2-expressing cells. Thus, Slit2 is an inhibitor and chemorepellent for dorsal thalamic axons. Collagen gel cocultures
Homeodomain transcription factors regulate development of embryos and cellular physiology in adult systems. Paired-type homeodomain genes constitute a subclass that has been particularly implicated in establishment of neuronal identity in the mammalian nervous system. We isolated fragments of eight homeodomain genes of this subclass expressed in the stellate ganglion of ... read more the North Atlantic long finned squid Loligo pealei (lp) [Note: Loligo pealei has been officially renamed Doryteuthis pealei. For reasons of uniformity and clarity Loligo pealei (lp) is used here]. Of the most abundant ones, we cloned a full length cDNA which encoded the squid ortholog of the paired-type homeodomain proteins Phox2a/b. The homology of lpPhox2 to invertebrate and mammalian Phox2 was limited to the homeodomain. In contrast to mouse Phox2b, lpPhox2 was unable to transactivate the dopamine beta-hydroxylase (DBH) promoter in a heterologous mammalian transfection system. In vivo, lpPhox2 was expressed in ...
Biology Assignment Help, Giant nerve fibres, Giant Nerve Fibres We now know that giant nerve fibres take place in the central nervous system of many polychaetes, oligochaetes, insects cephalopod etc. They are broader and longer as compared to the other, ordinary nerve fibres which are abo
Free download. Book file PDF easily for everyone and every device. You can download and read online homeobox gene expression in adult dorsal root ganglia is regeneration a recapitulation of development christina francisca vogelaar file PDF Book only if you are registered here. And also you can download or read online all Book PDF file that related with homeobox gene expression in adult dorsal root ganglia is regeneration a recapitulation of development christina francisca vogelaar book. Happy reading homeobox gene expression in adult dorsal root ganglia is regeneration a recapitulation of development christina francisca vogelaar Bookeveryone. Download file Free Book PDF homeobox gene expression in adult dorsal root ganglia is regeneration a recapitulation of development christina francisca vogelaar at Complete PDF Library. This Book have some digital formats such us :paperbook, ebook, kindle, epub, fb2 and another formats. Here is The CompletePDF Book Library. Its free to register here to get ...
Abstract: Abdominal ganglia of crayfish contain identifiable neuropils, commissures, longitudinal tracts, and vertical tracts. To determine the functional significance of this ganglionic framework, we backfilled the following types of neurons with cobalt chloride: sensory hair afferents, slow and fast extensor motor neurons, the segmental stretch receptor neurons, and their inhibitory accessory cells. After the cobalt ions were precipitated and intensified, we studied the central projections of the filled neurons within the ganglionic structures. All of the axons of these neurons exit or enter each of the first five abdominal ganglia through the second pair of nerves. Our description of the central projections of the hair afferents is the first in the literature. These afferents innervate the large ventral horseshoe neuropil (HN) in the core of each ganglion. This neuropil is homologous to the insect ventral association centers, which also process sensory information. Furthermore, we discovered ...
A retinal ganglion cell (RGC) is a type of neuron located near the inner surface (the ganglion cell layer) of the retina of the eye. It receives visual information from photoreceptors via two intermediate neuron types: bipolar cells and retina amacrine cells. Retina amacrine cells, particularly narrow field cells, are important for creating functional subunits within the ganglion cell layer and making it so that ganglion cells can observe a small dot moving a small distance. Retinal ganglion cells collectively transmit image-forming and non-image forming visual information from the retina in the form of action potential to several regions in the thalamus, hypothalamus, and mesencephalon, or midbrain. Retinal ganglion cells vary significantly in terms of their size, connections, and responses to visual stimulation but they all share the defining property of having a long axon that extends into the brain. These axons form the optic nerve, optic chiasm, and optic tract. A small percentage of ...
We describe here the cloning of mouse complementary DNAs encoding a novel protein, Rb-8 neural cell adhesion molecule (RNCAM), with a predicted extracellular region of five immunoglobulin Ca-type domains followed by two fibronectin type III domains, Alternative splicing is likely to generate two RNCAM isoforms, which are differently attached to the cell membrane, These structural features and overall sequence identity identify this protein as a novel member of a cell adhesion molecule subgroup together with vertebrate neural cell adhesion molecule, Aplysia cell adhesion molecule, and Drosophila fasciclin II, In insects, fasciclin II is present on a restricted subset of embryonic central nervous system axons where it controls selective axon fasciculation. Intriguingly, RNCAM likewise is expressed in subsets of olfactory and vomeronasal neurons with topographically defined axonal projections, The spatial expression RNCAM corresponds precisely to that of certain odorant receptor expression zones of ...

Retrograde Degeneration; Axon Reaction; Nissl Degeneration; Retrograde Degeneration, TransneuronalRetrograde Degeneration; Axon Reaction; Nissl Degeneration; Retrograde Degeneration, Transneuronal

Axon Reaction; Nissl Degeneration; Retrograde Degeneration, Transneuronal. On-line free medical diagnosis assistant. Ranked ... Pathologic changes that occur in the axon and cell body of a neuron proximal to an axonal lesion. The process is characterized ... Retrograde Degeneration (Axon Reaction; Nissl Degeneration; Retrograde Degeneration, Transneuronal). ...
more infohttps://lookfordiagnosis.com/mesh_info.php?term=Retrograde+Degeneration&lang=1

PRIME PubMed | Synaptic circuitry in the retinorecipient layers of the optic tectum of the lamprey (Lampetra fluviatilis). A...PRIME PubMed | Synaptic circuitry in the retinorecipient layers of the optic tectum of the lamprey (Lampetra fluviatilis). A...

Synapses of optic axons with GABA- and glutamate-containing elements in the optic tectum of Bufo marinus. ... Pretectal and tectal afferents to the dorsal lateral geniculate nucleus of the turtle: an electron microscopic axon tracing and ... Five types of axon terminals were identified and divided into two major categories. The first of these are GABA-immunonegative ... Five types of axon terminals were identified and divided into two major categories. The first of these are GABA-immunonegative ...
more infohttps://www.unboundmedicine.com/medline/citation/19252925/Synaptic_circuitry_in_the_retinorecipient_layers_of_the_optic_tectum_of_the_lamprey__Lampetra_fluviatilis___A_combined_hodological_GABA_and_glutamate_immunocytochemical_study_

Organization and development of horizontal cells in the goldfish retina, I: The use of monoclonal antibody AT101<...Organization and development of horizontal cells in the goldfish retina, I: The use of monoclonal antibody AT101<...

... which selectively labels both viable and formaldehyde-fixed horizontal cell axon terminals, but not their somas or axons, of ... which selectively labels both viable and formaldehyde-fixed horizontal cell axon terminals, but not their somas or axons, of ... which selectively labels both viable and formaldehyde-fixed horizontal cell axon terminals, but not their somas or axons, of ... which selectively labels both viable and formaldehyde-fixed horizontal cell axon terminals, but not their somas or axons, of ...
more infohttps://nebraska.pure.elsevier.com/en/publications/organization-and-development-of-horizontal-cells-in-the-goldfish--2

A method to deliver patterned electrical impulses to Schwann cells cultured on an artificial axon.  - PubMed - NCBIA method to deliver patterned electrical impulses to Schwann cells cultured on an artificial axon. - PubMed - NCBI

... and multiple tiny un-myelinated axons engulfed by a non-myelinating Schwann cell (u). Mitochondria are present inside the axon ... A method to deliver patterned electrical impulses to Schwann cells cultured on an artificial axon.. Merolli A1, Mao Y1, Voronin ... Top left: a schematic drawing of a Schwann cell wrapping around an axon (black) in transverse section and forming the myelin ... The fiber provides only the biophysical characteristics of an axon but does not contribute any molecular signaling. In our " ...
more infohttps://www.ncbi.nlm.nih.gov/pubmed/30762018

Axon Active - Agile Offshore Software Development CompanyAxon Active - Agile Offshore Software Development Company

Axon Active is a Swiss company, specializes in setup of customized offshore development and test teams. With a strong focus on ... With Axon Active, we found a very trustworthy partner. We have a cross-functional team at Axon Active, with a German product ... With every issue, Axon Active fully collaborates with us to solve it, including personal help from Axons Branch Manager if ... In the future, we plan to grow our partnership with Axon Active. Axon allows us to stay agile in the development process and ...
more infohttps://www.axonactive.com/

Axon | NasdaqAxon | Nasdaq

Sign up for our newsletter to get the latest on the transformative forces shaping the global economy, delivered every Thursday ...
more infohttps://www.nasdaq.com/videos/axon

axons | Tags | Cosmosaxons | Tags | Cosmos

Science magazine founded by Australias chief scientist Alan Finkel makes the latest discoveries accessible to everyone with beautiful pictures and great
more infohttps://cosmosmagazine.com/tags/axons

axons tagged stories - MIT Technology Reviewaxons tagged stories - MIT Technology Review

The mission of MIT Technology Review is to bring about better-informed and more conscious decisions about technology through authoritative, influential, and trustworthy journalism.
more infohttps://www.technologyreview.com/g/axons/

Samuel AxonSamuel Axon

Business Trends and Insights from American Express delivers insights and inspiration to help you run, grow and expand your business. Explore to learn trends in business and get valuable insights.
more infohttps://www.americanexpress.com/en-us/business/trends-and-insights/keywords/samuel-axon/

W32.Axon | SymantecW32.Axon | Symantec

W32.Axon - Symantec Security Response provides comprehensive internet protection expertise to guard against complex threats, ... W32.Axon is a virus that prepends itself to files with the .exe extension on drives C through Z. It also deletes files with . ...
more infohttps://www.symantec.com/security_response/writeup.jsp?docid=2004-050711-2936-99

Axon | anatomy | Britannica.comAxon | anatomy | Britannica.com

Some axons may be quite long, reaching, for example, from the spinal cord down to a toe. Most axons of ... Axon, portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically has one axon ... Some axons may be quite long, reaching, for example, from the spinal cord down to a toe. Most axons of vertebrates are enclosed ... More About Axon. 25 references found in Britannica articles. Assorted References. *major reference* In nervous system: Axon ...
more infohttps://www.britannica.com/science/axon

axon - Everything2.comaxon - Everything2.com

The longest axon in the human body would be those that run from the base of your spine down to your feet, the longest of which ... axon: a threadlike structure on which impulses are transmitted away from the main body of a nerve cell [from Greek, axon, axle ... The longest axon in the human body would be those that run from the base of your spine down to your feet, the longest of which ...
more infohttps://www.everything2.com/title/axon

Axone - Drugs.comAxone - Drugs.com

A list of US medications equivalent to Axone is available on the Drugs.com website. ... Axone is a medicine available in a number of countries worldwide. ... Ingredient matches for Axone. Ceftriaxone. Ceftriaxone is reported as an ingredient of Axone in the following countries:. * ...
more infohttps://www.drugs.com/international/axone.html

Axon OpticsAxon Optics

... is a high tech startup formed after a neuro-ophthalmologist, photonics researcher, and ophthalmic entrepreneur got ... Axon Optics is a high tech startup formed after a neuro-ophthalmologist, photonics researcher, and ophthalmic entrepreneur got ... Axon Optics specially tinted glasses block the light that has been implicated in exacerbating sensitivity to light. Control ...
more infohttps://askjan.org/vendors/Axon-Optics.cfm

Axon Theme - WordPress.comAxon Theme - WordPress.com

Axon is powered with boxed or wide layout that can be further customized to left sidebar, right sidebar or without sidebar ... Axon is a clean, creative and responsive WordPress blog theme. It has an eye-catching featured posts content area. ... Axon is a clean, creative and responsive WordPress blog theme. It has an eye-catching featured posts content area. Axon is ... Axon comes with five widget areas - one in the right or left sidebar, and up to four in the footer. The footer widget areas ...
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Axon collaterals ?Axon collaterals ?

... BilZ0r BilZ0r at TAKETHISOUThotmail.com Tue Dec 16 23:23:07 EST 2003 *Previous message: Axon collaterals ? ...
more infohttp://www.bio.net/bionet/mm/neur-sci/2003-December/056271.html

Axon collaterals ?Axon collaterals ?

... Doktor DynaSoar targeting at OMCL.mil Fri Dec 19 09:25:39 EST 2003 *Previous message: Axon collaterals ? ...
more infohttp://www.bio.net/bionet/mm/neur-sci/2003-December/056323.html

What Are Myelinated Axons? (with pictures)What Are Myelinated Axons? (with pictures)

Myelinated axons are parts of a neuron that are encapsulated by fatty layers called myelin sheaths. The sheaths keep the axons ... At the end of the axon are small branches called axon terminals. These connect to similar branches protruding from the soma of ... Myelinated axons are a portion of a neuron, or nerve cell, that is encapsulated by a fatty layer called the myelin sheath. Much ... The axon is long and skinny and acts like a kind of cellular electrical cord that plugs into the dendrites of the next cell. ...
more infohttps://www.wisegeek.com/what-are-myelinated-axons.htm

Brindusa Axons  InfoQ ProfileBrindusa Axon's InfoQ Profile

We care about the world in which we live and we want to make it a better place.. We are doing so by fulfilling our mission to accelerate the human side of software development.. We also donate 1% of our profit to different causes, which we as a company, as well as our employees, strongly believe in.. ...
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Infosys swoops on Axon • The RegisterInfosys swoops on Axon • The Register

Infosys swoops on Axon. Snaps up SAP firm. By Kelly Fiveash 26 Aug 2008 at 09:39 ... Axon consults with multinationals that use SAP as their enterprise platform.. It employs over 1,650 people and has a client ... Shares in Axon are currently trading at 602.00 pence, up 20 per cent, on the London Stock Exchange. ® ... Shares in computer software firm Axon Group jumped more than 20 per cent this morning after it agreed a £407.1m takeover from ...
more infohttps://www.theregister.co.uk/2008/08/26/infosys_buys_axon/

Axons in 3-D [image] | EurekAlert! Science NewsAxons in 3-D [image] | EurekAlert! Science News

Also shown are reconstructions of 50 myelinated axons from the ventroposterolateral nucleus of the thalamus from a similarly ... Also shown are reconstructions of 50 myelinated axons from the ventroposterolateral nucleus of the thalamus from a similarly ...
more infohttps://www.eurekalert.org/multimedia/pub/49014.php?from=224459

Axon Leggings | Society6Axon Leggings | Society6

Shop axon leggings that bring out your unique personality. Designed by thousands of artists from around the world, our printed ...
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Axon GuidanceAxon Guidance

... is the means whereby axon processesgrowing from differentiating nerve cells are guided to their targets during ... Axon guidance is the means whereby axon processes growing from differentiating nerve cells are guided to their targets during ... Major classes of axon guidance molecules and their receptors. Lam, region with homology to N‐terminal domains of laminin chains ... The growing axon tip, the growth cone, is essential to this process, being capable of locomotion and responding to molecular ...
more infohttp://www.els.net/WileyCDA/ElsArticle/refId-a0000799.html

Axon GrowthAxon Growth

... Carla Toro, Cranfield University, Bedfordshire, UK Catia Sousa, Cranfield University, Bedfordshire, UK David ... The tip of this growing axon displays a highly specialised and dynamic structure, called the growth cone. Growth cone sense ... Note that the peripheral region (dark green) has more actin filaments than the axon or central region (light green). Whereas ... Establishment of these connections involves the growth and extension of long thin processes, known as axons, from the main body ...
more infohttp://www.els.net/WileyCDA/ElsArticle/refId-a0000798.html

Molecule shown to repair damaged axons | Newsroom - McGill UniversityMolecule shown to repair damaged axons | Newsroom - McGill University

... brain and spinal cord injury A foray into plant biology led one researcher to discover that a natural molecule can repair axons ... The axons are stained in green and the tips of the growing axons, called growth cones, are stained in red. ... Kaplan theorized that fusicoccin-A could be an effective way of harnessing 14-3-3 to repair axons. To test this theory, he and ... The team found that the physical bonding of 14-3-3 and GCN1 is an important factor in fusicoccin-A-induced axon growth. Now ...
more infohttps://www.mcgill.ca/newsroom/channels/news/molecule-shown-repair-damaged-axons-266833
  • ZTE has just made its latest smartphone, the Axon 7 , available for preordering by way of its official US website , and at Amazon, Best Buy, B&H, and Newegg, for a price of $400, with shipping to start on July 27th of this year. (wirefly.com)
  • With the coming of the Axon 7, the $400 smartphone club just got a little more crowded. (wirefly.com)
  • ZTE is a repeat customer, with its original Axon smartphone having also integrated the FPC1025, which took aim at rivals in the high-end smartphone market. (findbiometrics.com)
  • Axon allows you to add links to your Facebook, Twitter, LinkedIn, Google Plus and Tumblr accounts in the theme's footer. (wordpress.com)
  • This is an exciting advance because the field has struggled to find treatments and identify targets for drugs that stimulate axon repair. (mcgill.ca)
  • The longest axon in the human body would be those that run from the base of your spine down to your feet, the longest of which probably controls the interosseus muscles which twitch your toe s from side to side. (everything2.com)
  • Also shown are reconstructions of 50 myelinated axons from the ventroposterolateral nucleus of the thalamus from a similarly prepared sample. (eurekalert.org)
  • Most individual axons are microscopic in diameter (typically about one micrometer (µm) across). (wikipedia.org)
  • Most axons branch, in some cases very profusely. (medicalxpress.com)
  • In comparison, the cerebellar granule cell axon is characterized by a single T-shaped branch node from which two parallel fibers extend. (wikipedia.org)
  • The largest white matter tract in the brain is the corpus callosum formed of some 20 million axons. (wikipedia.org)
  • Kaplan says future work should focus on better understanding the mechanisms by which fusicoccin-A improves axon repair. (mcgill.ca)
  • however in invertebrates such as insects the axon sometimes consists of several regions that function more or less independently of each other. (medicalxpress.com)
  • We have identified a novel strategy to promote axon regeneration with a family of small molecules that may be excellent candidates for future drug development," says Fournier. (mcgill.ca)
  • Axon Optics is a high tech startup formed after a neuro-ophthalmologist, photonics researcher, and ophthalmic entrepreneur got together during the summer of 2010 to help people with photosensitive migraines by using the latest research performed at the University of Utah's Moran Eye Center. (askjan.org)