Neural Pathways: Neural tracts connecting one part of the nervous system with another.Trimecaine: Acetanilide derivative used as a local anesthetic.Allylglycine: An inhibitor of glutamate decarboxylase and an antagonist of GAMMA-AMINOBUTYRIC ACID. It is used to induce convulsions in experimental animals.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.Neuronal Tract-Tracers: Substances used to identify the location and to characterize the types of NEURAL PATHWAYS.Vagus Nerve: The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).Vagotomy: The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.Sodium Lactate: The sodium salt of racemic or inactive lactic acid. It is a hygroscopic agent used intravenously as a systemic and urinary alkalizer.Nervous System Physiological Processes: Biological actions and events that constitute the functions of the NERVOUS SYSTEM.Hexamethonium: A nicotinic cholinergic antagonist often referred to as the prototypical ganglionic blocker. It is poorly absorbed from the gastrointestinal tract and does not cross the blood-brain barrier. It has been used for a variety of therapeutic purposes including hypertension but, like the other ganglionic blockers, it has been replaced by more specific drugs for most purposes, although it is widely used a research tool.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Afferent Pathways: Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.Nervous System Physiological Phenomena: Characteristic properties and processes of the NERVOUS SYSTEM as a whole or with reference to the peripheral or the CENTRAL NERVOUS SYSTEM.Wheat Germ Agglutinins: Lectins purified from the germinating seeds of common wheat (Triticum vulgare); these bind to certain carbohydrate moieties on cell surface glycoproteins and are used to identify certain cell populations and inhibit or promote some immunological or physiological activities. There are at least two isoforms of this lectin.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.Preoptic Area: Region of hypothalamus between the ANTERIOR COMMISSURE and OPTIC CHIASM.Septal Nuclei: Neural nuclei situated in the septal region. They have afferent and cholinergic efferent connections with a variety of FOREBRAIN and BRAIN STEM areas including the HIPPOCAMPAL FORMATION, the LATERAL HYPOTHALAMUS, the tegmentum, and the AMYGDALA. Included are the dorsal, lateral, medial, and triangular septal nuclei, septofimbrial nucleus, nucleus of diagonal band, nucleus of anterior commissure, and the nucleus of stria terminalis.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.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.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.Hypogastric Plexus: A complex network of nerve fibers in the pelvic region. The hypogastric plexus distributes sympathetic fibers from the lumbar paravertebral ganglia and the aortic plexus, parasympathetic fibers from the pelvic nerve, and visceral afferents. The bilateral pelvic plexus is in its lateral extent.Proto-Oncogene Proteins c-fos: Cellular DNA-binding proteins encoded by the c-fos genes (GENES, FOS). They are involved in growth-related transcriptional control. c-fos combines with c-jun (PROTO-ONCOGENE PROTEINS C-JUN) to form a c-fos/c-jun heterodimer (TRANSCRIPTION FACTOR AP-1) that binds to the TRE (TPA-responsive element) in promoters of certain genes.Neurons, Efferent: Neurons which send impulses peripherally to activate muscles or secretory cells.Hypothalamus: Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.Escape Reaction: Innate response elicited by sensory stimuli associated with a threatening situation, or actual confrontation with an enemy.Spinal Cord: A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.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.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.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Capsaicin: An alkylamide found in CAPSICUM that acts at TRPV CATION CHANNELS.Gastrointestinal Motility: The motor activity of the GASTROINTESTINAL TRACT.Amygdala: Almond-shaped group of basal nuclei anterior to the INFERIOR HORN OF THE LATERAL VENTRICLE of the TEMPORAL LOBE. The amygdala is part of the limbic system.Peristalsis: A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction.Vocalization, Animal: Sounds used in animal communication.Anorexia: The lack or loss of APPETITE accompanied by an aversion to food and the inability to eat. It is the defining characteristic of the disorder ANOREXIA NERVOSA.Motor Neurons: Neurons which activate MUSCLE CELLS.Limbic System: A set of forebrain structures common to all mammals that is defined functionally and anatomically. It is implicated in the higher integration of visceral, olfactory, and somatic information as well as homeostatic responses including fundamental survival behaviors (feeding, mating, emotion). For most authors, it includes the AMYGDALA; EPITHALAMUS; GYRUS CINGULI; hippocampal formation (see HIPPOCAMPUS); HYPOTHALAMUS; PARAHIPPOCAMPAL GYRUS; SEPTAL NUCLEI; anterior nuclear group of thalamus, and portions of the basal ganglia. (Parent, Carpenter's Human Neuroanatomy, 9th ed, p744; NeuroNames, (September 2, 1998)).Atropine: An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.Duodenum: The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.Habituation, Psychophysiologic: The disappearance of responsiveness to a repeated stimulation. It does not include drug habituation.Medulla Oblongata: The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.Functional Laterality: Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Body Temperature Regulation: The processes of heating and cooling that an organism uses to control its temperature.Sexual Behavior, Animal: Sexual activities of animals.Behavior, Animal: The observable response an animal makes to any situation.Sympathetic Nervous System: The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Neurons, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Myenteric Plexus: One of two ganglionated neural networks which together form the ENTERIC NERVOUS SYSTEM. The myenteric (Auerbach's) plexus is located between the longitudinal and circular muscle layers of the gut. Its neurons project to the circular muscle, to other myenteric ganglia, to submucosal ganglia, or directly to the epithelium, and play an important role in regulating and patterning gut motility. (From FASEB J 1989;3:127-38)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.Chemoreceptor Cells: Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.Reaction Time: The time from the onset of a stimulus until a response is observed.Thalamus: Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.Spinal Cord Injuries: Penetrating and non-penetrating injuries to the spinal cord resulting from traumatic external forces (e.g., WOUNDS, GUNSHOT; WHIPLASH INJURIES; etc.).Autonomic Nervous System: The ENTERIC NERVOUS SYSTEM; PARASYMPATHETIC NERVOUS SYSTEM; and SYMPATHETIC NERVOUS SYSTEM taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the CENTRAL NERVOUS SYSTEM, especially the HYPOTHALAMUS and the SOLITARY NUCLEUS, which receive information relayed from VISCERAL AFFERENTS.Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Conditioning (Psychology): A general term referring to the learning of some particular response.Serotonin: A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.Neuronal Plasticity: The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.Parasympathetic Nervous System: The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.Rats, Long-Evans: An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.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)Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Nerve Fibers: Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.Neuropeptides: Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.Muscle, Smooth: Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.Learning: Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.Eating: The consumption of edible substances.Nerve Net: A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Injections, Intraventricular: Injections into the cerebral ventricles.Neurotransmitter Agents: Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.Muscle Contraction: A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.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.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Trachea: The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.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.Ileum: The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.Dopamine: One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.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.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Leptin: A 16-kDa peptide hormone secreted from WHITE ADIPOCYTES. Leptin serves as a feedback signal from fat cells to the CENTRAL NERVOUS SYSTEM in regulation of food intake, energy balance, and fat storage.Visual Perception: The selecting and organizing of visual stimuli based on the individual's past experience.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.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.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.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.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.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.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.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.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.Mice, Inbred C57BLDisease 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.

A genetic approach to visualization of multisynaptic neural pathways using plant lectin transgene. (1/7484)

The wiring patterns among various types of neurons via specific synaptic connections are the basis of functional logic employed by the brain for information processing. This study introduces a powerful method of analyzing the neuronal connectivity patterns by delivering a tracer selectively to specific types of neurons while simultaneously transsynaptically labeling their target neurons. We developed a novel genetic approach introducing cDNA for a plant lectin, wheat germ agglutinin (WGA), as a transgene under the control of specific promoter elements. Using this method, we demonstrate three examples of visualization of specific transsynaptic neural pathways: the mouse cerebellar efferent pathways, the mouse olfactory pathways, and the Drosophila visual pathways. This strategy should greatly facilitate studies on the anatomical and functional organization of the developing and mature nervous system.  (+info)

even-skipped determines the dorsal growth of motor axons in Drosophila. (2/7484)

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)

Actions of a pair of identified cerebral-buccal interneurons (CBI-8/9) in Aplysia that contain the peptide myomodulin. (3/7484)

A combination of biocytin back-fills of the cerebral-buccal connectives and immunocytochemistry of the cerebral ganglion demonstrated that of the 13 bilateral pairs of cerebral-buccal interneurons in the cerebral ganglion, a subpopulation of 3 are immunopositive for the peptide myomodulin. The present paper describes the properties of two of these cells, which we have termed CBI-8 and CBI-9. CBI-8 and CBI-9 were found to be dye coupled and electrically coupled. The cells have virtually identical properties, and consequently we consider them to be "twin" pairs and refer to them as CBI-8/9. CBI-8/9 were identified by electrophysiological criteria and then labeled with dye. Labeled cells were found to be immunopositive for myomodulin, and, using high pressure liquid chromatography, the cells were shown to contain authentic myomodulin. CBI-8/9 were found to receive synaptic input after mechanical stimulation of the tentacles. They also received excitatory input from C-PR, a neuron involved in neck lengthening, and received a slow inhibitory input from CC5, a cell involved in neck shortening, suggesting that CBI-8/9 may be active during forward movements of the head or buccal mass. Firing of CBI-8 or CBI-9 resulted in the activation of a relatively small number of buccal neurons as evidenced by extracellular recordings from buccal nerves. Firing also produced local movements of the buccal mass, in particular a strong contraction of the I7 muscle, which mediates radula opening. CBI-8/9 were found to produce a slow depolarization and rhythmic activity of B48, the motor neuron for the I7 muscle. The data provide continuing evidence that the small population of cerebral buccal interneurons is composed of neurons that are highly diverse in their functional roles. CBI-8/9 may function as a type of premotor neuron, or perhaps as a peptidergic modulatory neuron, the functions of which are dependent on the coactivity of other neurons.  (+info)

C-PR neuron of Aplysia has differential effects on "Feeding" cerebral interneurons, including myomodulin-positive CBI-12. (4/7484)

Head lifting and other aspects of the appetitive central motive state that precedes consummatory feeding movements in Aplysia is promoted by excitation of the C-PR neuron. Food stimuli activate C-PR as well as a small population of cerebral-buccal interneurons (CBIs). We wished to determine if firing of C-PR produced differential effects on the various CBIs or perhaps affected all the CBIs uniformly as might be expected for a neuron involved in producing a broad undifferentiated arousal state. We found that when C-PR was fired, it produced a wide variety of effects on various CBIs. Firing of C-PR evoked excitatory input to a newly identified CBI (CBI-12) the soma of which is located in the M cluster near the previously identified CBI-2. CBI-12 shares certain properties with CBI-2, including a similar morphology and a capacity to drive rhythmic activity of the buccal-ganglion. Unlike CBI-2, CBI-12 exhibits myomodulin immunoreactivity. Furthermore when C-PR is fired, CBI-12 receives a polysynaptic voltage-dependent slow excitation, whereas, CBI-2 receives relatively little input. C-PR also polysynaptically excites other CBIs including CBI-1 and CBI-8/9 but produces inhibition in CBI-3. In addition, firing of C-PR inhibits plateau potentials in CBI-5/6. The data suggest that activity of C-PR may promote the activity of one subset of cerebral-buccal interneurons, perhaps those involved in ingestive behaviors that occur during the head-up posture. C-PR also inhibits some cerebral-buccal interneurons that may be involved in behaviors in which C-PR activity is not required or may even interfere with other feeding behaviors such as rejection or grazing, that occur with the head down.  (+info)

Central pattern generator for escape swimming in the notaspid sea slug Pleurobranchaea californica. (5/7484)

Escape swimming in the notaspid opisthobranch Pleurobranchaea is an episode of alternating dorsal and ventral body flexions that overrides all other behaviors. We have explored the structure of the central pattern generator (CPG) in the cerebropleural ganglion as part of a study of neural network interactions underlying decision making in normal behavior. The CPG comprises at least eight bilaterally paired interneurons, each of which contributes and is phase-locked to the swim rhythm. Dorsal flexion is mediated by hemiganglion ensembles of four serotonin-immunoreactive neurons, the As1, As2, As3, and As4, and an electrically coupled pair, the A1 and A10 cells. When stimulated, A10 commands fictive swimming in the isolated CNS and actual swimming behavior in whole animals. As1-4 provide prolonged, neuromodulatory excitation enhancing dorsal flexion bursts and swim cycle number. Ventral flexion is mediated by the A3 cell and a ventral swim interneuron, IVS, the soma of which is yet unlocated. Initiation of a swim episode begins with persistent firing in A10, followed by recruitment of As1-4 and A1 into dorsal flexion. Recurrent excitation within the As1-4 ensemble and with A1/A10 may reinforce coactivity. Synchrony among swim interneuron partners and bilateral coordination is promoted by electrical coupling among the A1/A10 and As4 pairs, and among unilateral As2-4, and reciprocal chemical excitation between contralateral As1-4 groups. The switch from dorsal to ventral flexion coincides with delayed recruitment of A3, which is coupled electrically to A1, and with recurrent inhibition from A3/IVS to A1/A10. The alternating phase relation may be reinforced by reciprocal inhibition between As1-4 and IVS. Pleurobranchaea's swim resembles that of the nudibranch Tritonia; we find that the CPGs are similar in many details, suggesting that the behavior and network are primitive characters derived from a common pleurobranchid ancestor.  (+info)

Disrupted temporal lobe connections in semantic dementia. (6/7484)

Semantic dementia refers to the variant of frontotemporal dementia in which there is progressive semantic deterioration and anomia in the face of relative preservation of other language and cognitive functions. Structural imaging and SPECT studies of such patients have suggested that the site of damage, and by inference the region critical to semantic processing, is the anterolateral temporal lobe, especially on the left. Recent functional imaging studies of normal participants have revealed a network of areas involved in semantic tasks. The present study used PET to examine the consequences of focal damage to the anterolateral temporal cortex for the operation of this semantic network. We measured PET activation associated with a semantic decision task relative to a visual decision task in four patients with semantic dementia compared with six age-matched normal controls. Normals activated a network of regions consistent with previous studies. The patients activated some areas consistently with the normals, including some regions of significant atrophy, but showed substantially reduced activity particularly in the left posterior inferior temporal gyrus (iTG) (Brodmann area 37/19). Voxel-based morphometry, used to identify the regions of structural deficit, revealed significant anterolateral temporal atrophy (especially on the left), but no significant structural damage to the posterior inferior temporal lobe. Other evidence suggests that the left posterior iTG is critically involved in lexical-phonological retrieval: the lack of activation here is consistent with the observation that these patients are all anomic. We conclude that changes in activity in regions distant from the patients' structural damage support the argument that their prominent anomia is due to disrupted temporal lobe connections.  (+info)

Specification of distinct dopaminergic neural pathways: roles of the Eph family receptor EphB1 and ligand ephrin-B2. (7/7484)

Dopaminergic neurons in the substantia nigra and ventral tegmental area project to the caudate putamen and nucleus accumbens/olfactory tubercle, respectively, constituting mesostriatal and mesolimbic pathways. The molecular signals that confer target specificity of different dopaminergic neurons are not known. We now report that EphB1 and ephrin-B2, a receptor and ligand of the Eph family, are candidate guidance molecules for the development of these distinct pathways. EphB1 and ephrin-B2 are expressed in complementary patterns in the midbrain dopaminergic neurons and their targets, and the ligand specifically inhibits the growth of neurites and induces the cell loss of substantia nigra, but not ventral tegmental, dopaminergic neurons. These studies suggest that the ligand-receptor pair may contribute to the establishment of distinct neural pathways by selectively inhibiting the neurite outgrowth and cell survival of mistargeted neurons. In addition, we show that ephrin-B2 expression is upregulated by cocaine and amphetamine in adult mice, suggesting that ephrin-B2/EphB1 interaction may play a role in drug-induced plasticity in adults as well.  (+info)

Structural maturation of neural pathways in children and adolescents: in vivo study. (8/7484)

Structural maturation of fiber tracts in the human brain, including an increase in the diameter and myelination of axons, may play a role in cognitive development during childhood and adolescence. A computational analysis of structural magnetic resonance images obtained in 111 children and adolescents revealed age-related increases in white matter density in fiber tracts constituting putative corticospinal and frontotemporal pathways. The maturation of the corticospinal tract was bilateral, whereas that of the frontotemporal pathway was found predominantly in the left (speech-dominant) hemisphere. These findings provide evidence for a gradual maturation, during late childhood and adolescence, of fiber pathways presumably supporting motor and speech functions.  (+info)

  • Based on the con-temporary feedback neural circuits of pain transmission in spinal cord, it is summarized that the Aδ- and C-fibers relay the sensory noxious signals to the laminae I, II and V of dorsal spinal horn, and in turn activate the peria-queductal grey (PAG) in midbrain, which feedbacks via raphe to inhibit the nociceptive transmission of spinal cord. (
  • The dual-pathway model has been proposed to explain the heterogeneity in symptoms of attention deficit hyperactivity disorder (ADHD) by two independent psychological pathways based on distinct brain circuits. (
  • Time coding, may also be important for the flow of neural information through circuits that drive behavior ( Salinas and Sejnowski, 2001 ). (
  • Forgetting over time and the acute forgetting of conflicting memory during reversal learning rely on separable neural circuits. (
  • Our results suggest that aromatization of testosterone into estrogen is important for the development and activation of neural circuits that control male territorial behaviors. (
  • In this chapter, we describe some of the most commonly used rodent models of alcohol intake and seeking as well as the methods used to identify the neural structures and circuits involved in alcohol-mediated behavior. (
  • Actual studies have been done on the brains of monks to show meditation's effect on neural circuits of the brain. (
  • Our data demonstrate that nucleotides and EGF induce converging, but also differential, intracellular signaling pathways and suggest that they carry the potential to act synergistically in the control of cell proliferation and cell survival in adult neurogenesis. (
  • Disruption of the pathways controlling NPC biology has been implicated in various pathologies, including autism ( 3 ), Treacher Collins syndrome ( 4 ), and neural tube defects ( 5 ), emphasizing the importance of gaining a better understanding of the underlying molecular events and how they may be manipulated to treat and prevent such pathologies. (
  • Neural tube defects result from failure to completely close neural tubes during development. (
  • Maternal diabetes is a substantial risk factor for neural tube defects, and available evidence suggests that the mechanism that links hyperglycemia to neural tube defects involves oxidative stress and apoptosis. (
  • We demonstrated that maternal hyperglycemia correlated with activation of the apoptosis signal-regulating kinase 1 (ASK1) in the developing neural tube, and Ask1 gene deletion was associated with reduced neuroepithelial cell apoptosis and development of neural tube defects. (
  • Hyperglycemia-induced apoptosis and the development of neural tube defects were reduced with genetic ablation of either FoxO3a or Casp8 or inhibition of ASK1 by thioredoxin. (
  • Examination of human neural tissues affected by neural tube defects revealed increased activation or abundance of ASK1, FoxO3a, TRADD, and caspase 8. (
  • Thus, activation of an ASK1-FoxO3a-TRADD-caspase 8 pathway participates in the development of neural tube defects, which could be prevented by inhibiting intermediates in this cascade. (
  • The failure of neurulation or neural tube closure results in neural tube defects (NTDs), with anencephaly and spina bifida being the two most common types in humans. (
  • For 20 years, scientists have known of a gene involved in neural tube defects (such as spina bifida), but until now it was not known exactly what causes this gene to malfunctions during diabetic pregnancies. (
  • Although it would appear that the way to prevent neural tube defects would be to stop Dnmt3b, Dr. Loeken cautions against such radical treatment. (
  • Neural tube defects happen in non-diabetic pregnancies as well, affecting about 1,500 births in the US every year and around 300,000 worldwide. (
  • Dr. Loeken's research has already caught the attention of other scientists working on neural tube defects. (
  • Mary R. Loeken, Ph.D., Investigator in the Section on Islet Cell and Regenerative Biology at Joslin Diabetes Center and Associate Professor of Medicine at Harvard Medical School, has discovered a molecular pathway responsible for neural tube defects in diabetic pregnancies. (
  • The latter so-called "psychogenic" response is anticipatory in nature and involves brain pathways responsible for innate defense programs or memory of aversive events (Herman et al. (
  • Know that transformation is always possible and that you can create new brain pathways whenever you're ready to make the shift. (
  • Researchers at the Hebrew University of Jerusalem have discovered that a neuronal pathway -- part of the autonomic nervous system -- reaches the bones and participates in the control of bone development. (
  • They further found that the newly discovered neuronal pathway, which includes interleukin-1 in the brain and the parasympathetic subsystem, also controls the heart rate. (
  • The neural cell adhesion molecule L1 plays a key role in nervous system development including neuronal migration, neurite growth, and axonal fasciculation. (
  • Self-renewing, multipotent neural precursor cells (NPCs) are capable of terminally differentiating into neuronal and glial lineages during development and in the adult nervous system ( 1 , 2 ). (
  • Neural precursor cells (NPCs) have the ability to self-renew and to give rise to neuronal and glial lineages. (
  • As such, it seems to be susceptible to genetic changes also seen in a variety of other neuroectodermal and neuronal tumors, including activation of Sonic hedgehog and phosphoinositide-3-kinase/Akt pathways. (
  • The authors sought to test whether the hypothesized cognitive and motivational pathways have separable neural correlates.In a longitudinal community-based cohort of 1,963 adolescents, the neuroanatomical correlates of ADHD were identified by a voxel-wise association analysis and then validated using an independent clinical sample (99 never-medicated patients with ADHD, 56 medicated patients with ADHD, and 267 healthy control subjects). (
  • We have previously shown that neural progenitor cells cultured as neurospheres from the adult mouse SVZ express functional P2Y 1 and P2Y 2 receptors and that the two respective receptor agonists, ADPβS and UTP, activate rapid intracellular Ca 2+ transients. (
  • These findings support the notion that spinal opioid receptors stimulate a neural pathway that uses nonopioid neurotransmitters to confer cardioprotection from ischemia reperfusion injury. (
  • Neural cell adhesion molecule L1: signaling pathways and growth cone motility. (
  • Signaling pathways stimulated by growth factors include activation of mitogen-activated protein (MAP) kinase. (
  • The PI3K-AKT-FoxO signaling pathway plays a central role in diverse physiological processes relevant to aging and cancer. (
  • Mammalian calvarial development and homeostasis are tightly regulated processes, dependent on the interplay of osteoblasts and osteoclasts and orchestrated by key, highly conserved, signaling pathways. (
  • Much progress has been made in recent years in defining the multiple signaling pathways, which confer osteogenic potential and regenerative capacity on the embryologically disparate calvarial bones. (
  • In this review we will explain how it has been possible to progress from a deeper understanding of the embryonic origin of the mammalian skull vault to rigorous in vivo and in vitro analysis of the differences in activity of key signaling pathways between the neural crest-derived frontal bones and the paraxial mesoderm-derived parietal bones. (
  • A finite number of signaling pathways are repurposed during animal development to regulate an extraordinary array of cellular decisions. (
  • The MAPK signaling pathway is a three-component module with the MAPK kinase kinase (MAP3K) as the initiator, MAPK kinase (MAPKK), and MAPK. (
  • These findings may reveal broader and stage-specific physiological roles of Wnt signaling during neural development. (
  • It is therefore important to gain insight into the underlying downstream signaling pathways. (
  • Here, we investigated signaling pathways elicited by ADPβS, UTP and epidermal growth factor (EGF). (
  • the potential multiplicity of relevant intercellular signaling pathways and the fine tuning of epigenetic gene regulation is still largely undefined ( Hsieh and Gage, 2004 ). (
  • A bone morphogenetic protein (BMP) signaling pathway is implicated in dorsoventral patterning in Xenopus. (
  • Our data indicate that TRBP is a novel transcriptional coactivator of the Notch signaling pathway playing an important role in neural stem cell regulation during mammalian brain development. (
  • Since then, human and mouse genetics, combined with cellular and developmental studies, have helped to unravel the role of this signaling pathway during development and adulthood. (
  • Our data demonstrate the consistency of LPA effects across various sources of human NS/PCs, rendering hESCs and iPSCs valuable models for studying lysophospholipid signaling in human neural cells. (
  • A neural pathway connects one part of the nervous system to another using bundles of axons called tracts. (
  • As in the bone and the heart, the new pathway might have an important function as well in other organs controlled by the autonomic nervous system. (
  • Neural tracts connecting one part of the nervous system with another. (
  • Neurulation, a key process during embryogenesis, leads to formation of the neural tube, which eventually develops into the central nervous system. (
  • Fundamentals of Anatomy & Physiology, 8e (Martini) Chapter 15 Neural Integration I: Sensory Pathways and the Somatic Nervous Multiple Choice Questions 1) S y s t e m The term general senses refers to sensitivity to all of the following, except A) temperature. (
  • In this review, we will summarize the known functions of the EDN3/EDNRB pathway during neural crest development, with a specific focus on recent scientific advances, and the enteric nervous system in normal and pathological conditions. (
  • The sensory nerves transfer the coded activity to the central nervous system, while the thalamus processes and then relays the neural responses. (
  • We conclude that the STN coordinates motor behavior through differential neural pathways depending on the state of DA transmission. (
  • Though seemingly instantaneous, our responses to life's many sights and sounds are the result of neural pathways that select the information that ultimately determines our behavior. (
  • Princeton University researchers tracked the neural activity of female fruit flies being courted by males to capture the process through which an outside stimulus causes a change in behavior. (
  • These results provide a clear and relatively simpler diagram of the stimulus-to-behavior neural process frequently carried out by more complicated brains such as that in humans, explained Mala Murthy , a professor of molecular biology and the Princeton Neuroscience Institute . (
  • A well-worn neural pathway equals a default to an unconscious behavior. (
  • The pathways present a challenge when you are ready to change a habit or behavior. (
  • In the developing retina, ATP was found to be essential for the coordinate proliferation and migration of neural precursors ( Martins and Pearson, 2008 ). (
  • The discovery of SOX2-LIN28/let-7 pathway that maintains both NPC proliferation and neurogenic potential will enhance our understanding and therapeutic development relevant to neurodegeneration and brain tumors. (
  • In conclusion, we discovered the SOX2-LIN28/let-7 pathway as a unique molecular mechanism governing NPC proliferation and neurogenic potential. (
  • The neural cell adhesion molecule (N-CAM) inhibits astrocyte proliferation in vitro and in vivo , and this effect is partially reversed by the glucocorticoid antagonist RU-486. (
  • Together, these findings indicate that homophilic N-CAM binding leads to inhibition of astrocyte proliferation via a pathway involving the glucocorticoid receptor and that the ability of N-CAM to influence astrocyte proliferation and neurite outgrowth involves different signal pathways. (
  • The Hippo pathway uses negative feedback through its transcriptional effector Yki for homeostatic control of proliferation. (
  • a ) a wide variety of neural markers, ( b ) members of the Sonic hedgehog pathway, ( c ) members of the phosphoinositide-3-kinase/Akt cell proliferation pathway, and ( d ) known therapeutic targets. (
  • Recent work performed in chicks, zebrafish and frogs has shown that the non-canonical Wnt-PCP (planar cell polarity) pathway plays a major role in neural crest migration. (
  • The sympathetic pathway, on the other hand, generally works to promote maintenance of the body at rest. (
  • In this re-view, it is attempted to newly delineate the underlying neural pathways for this post-sensory nociceptive-sympathetic coupling. (
  • A genetically modified mice model suggests that low-level electroacupuncture at hindlegs reduced inflammation not though the spleen, but a different neural pathway involving the vagus nerves and the adrenal glands. (
  • Marianne Bronner-Fraser, Effects of different fragments of the fibronectin molecule on latex bead translocation along neural crest migratory pathways, Developmental Biology, Volume 108, Issue 1, 1985, Pages 131-145, ISSN 0012-1606, (
  • Yavich and Tiihonen 2000) and activation of central corticotropin-releasing factor (CRF) pathways (Heilig and Koob 2007). (
  • The neural fate commitment of pluripotent stem cells requires the repression of extrinsic inhibitory signals and the activation of intrinsic positive transcription factors. (
  • Activation of neural pathways associated with sexual arousal in non-hu" by Craig F. Ferris, Charles T. Snowdon et al. (
  • The GM-CSF-activated cellular signal pathways were specifically inhibited by the pretreatment of GM-CSF receptor α antibody, suggesting the specificity of the signal activation. (
  • The experiment using specific inhibitors (AG490) to the JAK/STAT pathway showed that JAK2/STAT5 cascade was well preserved and activated by GM-CSF in A172 cells, while STAT5 was activated by GM-CSF without JAK2 activation in SK-N-(EB)2 cells. (
  • After microinjection into embryos at the time of neural crest migration, uncoated latex polystyrene beads were found to translocate to ventral sites and to settle in the vicinity of endogenous neural crest derivatives. (
  • The results suggest that the cell-binding domain is primarily responsible for restriction of fibronectin beads from the ventral neural crest pathway. (
  • In Xenopus laevis embryos, anti-tenascin stained the dorsal fin matrix and ECM along the ventral route of migration, but not the ECM found laterally between the ectoderm and somites where neural crest cells do not migrate. (
  • This study tests whether flicker adaptation also reduces neural transmission speed for suprathreshold stimuli by measuring the response time to a suprathreshold disc. (
  • Overall, the results confirm that flicker adaptation reduces neural transmission speed for suprathreshold stimuli (consistent with working hypothesis #1), but also show that transmission speed for a stimulus presented to only one eye can be speeded up by adding adaptation in the fellow eye (contrary to #2). (
  • The neural pathways were examined by recording locomotor activity, under a 13 h light to 13 h dark cycle, after the optic nerves were unilaterally severed and the contralateral optic stalk was partially destroyed near the lobula. (
  • Researchers at the University at Buffalo have discovered a previously unknown neural pathway that can regulate changes made in the brain due to cocaine use, providing new insight into the molecular basis of cocaine addiction. (
  • The newly discovered pathway has a key role in controlling bone density during adolescence, which in turn determines the skeletal resistance to fracture throughout one's entire life, say the researchers. (
  • The researchers have built and tested in mice neural probes that hold what are believed to be the smallest implantable LEDs ever made. (
  • Researchers at the University of Pittsburgh have reported using a new imaging technique called High-Definition Fiber Tracking (HDFT) to identify the disrupted neural pathways (paths made up of brain cells that communicate with one another) in patients with traumatic brain injury. (
  • Researchers have identified a pathway near the midbrain where neural messages for taste and pain converge, a new study reports. (
  • Although this method provides a fantastically detailed snapshot of the neural wiring pattern, the information about the dynamic transmission of nerve impulses in the living brain is lost. (
  • One of the neural markers, nerve growth factor receptor, represents a promising diagnostic tool for CCSK. (
  • RIPC was induced by 3 cycles of 5 min left femoral artery occlusion interspersed with 5 min reperfusion before prolonged myocardial ischaemia with or without femoral vein occlusion (humoral pathway), femoral nerve resection and/or sciatic nerve resection (neural pathway). (
  • With serial sections we found neural branches and fibers extending from hyponeural part of radial nerve towards LMBW and circular muscles of body wall. (
  • Retina: The pupillary reflex pathway begins with the photosensitive retinal ganglion cells , which convey information via the optic nerve , the most peripheral, distal, portion of which is the optic disc . (
  • Neural networks are groups of nerve cells that work either independently or as a unit in a healthy brain. (
  • Neural pathways are like superhighways of nerve cells that transmit messages. (
  • Recent insights into modalities and regulatory pathways involved in brain endothelial cell death will be described. (
  • In this proposal, we aim to develop genetic tools that will greatly contribute to our understanding by concurrently elucidating precise gustatory neural pathways within the same animal, and then use these tools to test our hypothesis that gustatory information for different taste modalities is transmitted via specific ascending neural pathways. (
  • These mutually exclusive cell fates are established by the Hippo pathway kinase warts and the growth regulator gene melted , which repress each other's expression. (
  • Additionally, two pathways activated in CCSK (Sonic hedgehog and phosphoinositide-3-kinase/Akt) have also been implicated in other pediatric neural tumors. (
  • Our laboratory has demonstrated that this distinct embryonic origin of frontal and parietal bones confer differences in embryonic and postnatal osteogenic potential and skeletal regenerative capacity, with frontal neural crest derived osteoblasts benefitting from greater osteogenic potential. (
  • A neural tube is the body's first step in assembling the spinal cord and the brain, which takes place within the first two to four weeks of gestation. (
  • Using a rodent model of myocardial ischemia reperfusion injury with infarct size as the primary outcome, we tested the hypothesis that spinal opioids confer this beneficial effect via a neural pathway. (
  • Neural Correlates of the Dual-Pathway Model for ADHD in Adolescents. (
  • The baseline gray matter volume of the posterior occipital cluster predicted the inattention symptoms in a 2-year follow-up and was associated with the genetic risk for ADHD.The dual-pathway model has both shared and separable neuroanatomical correlates, and the shared correlate in the occipital cortex has the potential to serve as an imaging trait marker of ADHD, especially the inattention symptom domain. (