Depolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during neurotransmission. Excitatory postsynaptic potentials can singly or in summation reach the trigger threshold for ACTION POTENTIALS.
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.
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.
Use of electric potential or currents to elicit biological responses.
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.
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.
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.
The D-enantiomer is a potent and specific antagonist of NMDA glutamate receptors (RECEPTORS, N-METHYL-D-ASPARTATE). The L form is inactive at NMDA receptors but may affect the AP4 (2-amino-4-phosphonobutyrate; APB) excitatory amino acid receptors.
The function of opposing or restraining the excitation of neurons or their target excitable 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.
Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
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.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
A persistent increase in synaptic efficacy, usually induced by appropriate activation of the same synapses. The phenomenological properties of long-term potentiation suggest that it may be a cellular mechanism of learning and memory.
A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.
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.
Drugs that bind to but do not activate GABA RECEPTORS, thereby blocking the actions of endogenous GAMMA-AMINOBUTYRIC ACID and GABA RECEPTOR AGONISTS.
A potent excitatory amino acid antagonist with a preference for non-NMDA iontropic receptors. It is used primarily as a research tool.
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).
Hyperpolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during NEUROTRANSMISSION. They are local changes which diminish responsiveness to excitatory signals.
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.
Neurons which activate MUSCLE CELLS.
A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.
Extensions of the nerve cell body. They are short and branched and receive stimuli from other NEURONS.
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.
An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.
The most common inhibitory neurotransmitter in the central nervous system.
A class of ionotropic glutamate receptors characterized by their affinity for the agonist AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid).
The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.
The voltages across pre- or post-SYNAPTIC MEMBRANES.
Drugs that bind to and activate excitatory amino acid receptors.
A noncompetitive antagonist at GABA-A receptors and thus a convulsant. Picrotoxin blocks the GAMMA-AMINOBUTYRIC ACID-activated chloride ionophore. Although it is most often used as a research tool, it has been used as a CNS stimulant and an antidote in poisoning by CNS depressants, especially the barbiturates.
Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.
One of four subsections of the hippocampus described by Lorente de No, located furthest from the DENTATE GYRUS.
Neurotransmitter receptors located on or near presynaptic terminals or varicosities. Presynaptic receptors which bind transmitter molecules released by the terminal itself are termed AUTORECEPTORS.
An amino acid that, as the D-isomer, is the defining agonist for the NMDA receptor subtype of glutamate receptors (RECEPTORS, NMDA).
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.
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)
Neural tracts connecting one part of the nervous system with another.
An IBOTENIC ACID homolog and glutamate agonist. The compound is the defining agonist for the AMPA subtype of glutamate receptors (RECEPTORS, AMPA). It has been used as a radionuclide imaging agent but is more commonly used as an experimental tool in cell biological studies.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
A subset of GABA RECEPTORS that signal through their interaction with HETEROTRIMERIC G-PROTEINS.
A GAMMA-AMINOBUTYRIC ACID derivative that is a specific agonist of GABA-B RECEPTORS. It is used in the treatment of MUSCLE SPASTICITY, especially that due to SPINAL CORD INJURIES. Its therapeutic effects result from actions at spinal and supraspinal sites, generally the reduction of excitatory transmission.
Cell surface receptors that bind signalling molecules released by neurons and convert these signals into intracellular changes influencing the behavior of cells. Neurotransmitter is used here in its most general sense, including not only messengers that act to regulate ion channels, but also those which act on second messenger systems and those which may act at a distance from their release sites. Included are receptors for neuromodulators, neuroregulators, neuromediators, and neurohumors, whether or not located at synapses.
Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.
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.
Drugs that bind to but do not activate GABA-B RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-B RECEPTOR AGONISTS.
Cell-surface proteins that bind glutamate and trigger changes which influence the behavior of cells. Glutamate receptors include ionotropic receptors (AMPA, kainate, and N-methyl-D-aspartate receptors), which directly control ion channels, and metabotropic receptors which act through second messenger systems. Glutamate receptors are the most common mediators of fast excitatory synaptic transmission in the central nervous system. They have also been implicated in the mechanisms of memory and of many diseases.
Clusters of neuronal cell bodies in invertebrates. Invertebrate ganglia may also contain neuronal processes and non-neuronal supporting cells. Many invertebrate ganglia are favorable subjects for research because they have small numbers of functional neuronal types which can be identified from one animal to another.
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.
The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (COCHLEAR NERVE) which is concerned with hearing and a vestibular part (VESTIBULAR NERVE) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the SPIRAL GANGLION and project to the cochlear nuclei (COCHLEAR NUCLEUS). The fibers of the vestibular nerve arise from neurons of Scarpa's ganglion and project to the VESTIBULAR NUCLEI.
GRAY MATTER situated above the GYRUS HIPPOCAMPI. It is composed of three layers. The molecular layer is continuous with the HIPPOCAMPUS in the hippocampal fissure. The granular layer consists of closely arranged spherical or oval neurons, called GRANULE CELLS, whose AXONS pass through the polymorphic layer ending on the DENDRITES of PYRAMIDAL CELLS in the hippocampus.
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.
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)
A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.
Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop.
Postsynaptic potentials generated from a release of neurotransmitters from a presynaptic nerve terminal in the absence of an ACTION POTENTIAL. They may be m.e.p.p.s (miniature EXCITATORY POSTSYNAPTIC POTENTIALS) or m.i.p.p.s (miniature INHIBITORY POSTSYNAPTIC POTENTIALS).
A pathway of fibers that originates in the lateral part of the ENTORHINAL CORTEX, perforates the SUBICULUM of the HIPPOCAMPUS, and runs into the stratum moleculare of the hippocampus, where these fibers synapse with others that go to the DENTATE GYRUS where the pathway terminates. It is also known as the perforating fasciculus.
Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.
Drugs that bind to but do not activate GABA-A RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-A RECEPTOR AGONISTS.
An alkaloid found in the seeds of STRYCHNOS NUX-VOMICA. It is a competitive antagonist at glycine receptors and thus a convulsant. It has been used as an analeptic, in the treatment of nonketotic hyperglycinemia and sleep apnea, and as a rat poison.
Cell surface proteins that bind glutamate and act through G-proteins to influence second messenger systems. Several types of metabotropic glutamate receptors have been cloned. They differ in pharmacology, distribution, and mechanisms of action.
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.
Refers to animals in the period of time just after birth.
Clusters of neurons and their processes in the autonomic nervous system. In the autonomic ganglia, the preganglionic fibers from the central nervous system synapse onto the neurons whose axons are the postganglionic fibers innervating target organs. The ganglia also contain intrinsic neurons and supporting cells and preganglionic fibers passing through to other ganglia.
A broad-spectrum excitatory amino acid antagonist used as a research tool.
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.
The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.
An opisthobranch mollusk of the order Anaspidea. It is used frequently in studies of nervous system development because of its large identifiable neurons. Aplysiatoxin and its derivatives are not biosynthesized by Aplysia, but acquired by ingestion of Lyngbya (seaweed) species.
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)
Axons of certain cells in the DENTATE GYRUS. They project to the polymorphic layer of the dentate gyrus and to the proximal dendrites of PYRAMIDAL CELLS of the HIPPOCAMPUS. These mossy fibers should not be confused with mossy fibers that are cerebellar afferents (see 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.
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.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)
Elements of limited time intervals, contributing to particular results or situations.
Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure.
A class of ionotropic glutamate receptors characterized by their affinity for KAINIC ACID.
One of two ganglionated neural networks which together form the enteric nervous system. The submucous (Meissner's) plexus is in the connective tissue of the submucosa. Its neurons innervate the epithelium, blood vessels, endocrine cells, other submucosal ganglia, and myenteric ganglia, and play an important role in regulating ion and water transport. (From FASEB J 1989;3:127-38)
Ganglia of the parasympathetic nervous system, including the ciliary, pterygopalatine, submandibular, and otic ganglia in the cranial region and intrinsic (terminal) ganglia associated with target organs in the thorax and abdomen.
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.
A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.
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.
The time from the onset of a stimulus until a response is observed.
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.
An amino acid formed by cyclization of leucine. It has cytostatic, immunosuppressive and antineoplastic activities.
A genus of marine sea slugs in the family Glaucidae, superorder GASTROPODA, found on the Pacific coast of North America. They are used in behavioral and neurological laboratory studies.
A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)
Cell-surface proteins that bind GAMMA-AMINOBUTYRIC ACID with high affinity and trigger changes that influence the behavior of cells. GABA-A receptors control chloride channels formed by the receptor complex itself. They are blocked by bicuculline and usually have modulatory sites sensitive to benzodiazepines and barbiturates. GABA-B receptors act through G-proteins on several effector systems, are insensitive to bicuculline, and have a high affinity for L-baclofen.
Therapeutic introduction of ions of soluble salts into tissues by means of electric current. In medical literature it is commonly used to indicate the process of increasing the penetration of drugs into surface tissues by the application of electric current. It has nothing to do with ION EXCHANGE; AIR IONIZATION nor PHONOPHORESIS, none of which requires current.
Endogenous compounds and drugs that bind to and activate GAMMA-AMINOBUTYRIC ACID receptors (RECEPTORS, GABA).
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.
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.
The output neurons of the cerebellar cortex.
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.
Area of the parietal lobe concerned with receiving sensations such as movement, pain, pressure, position, temperature, touch, and vibration. It lies posterior to the central sulcus.
A persistent activity-dependent decrease in synaptic efficacy between NEURONS. It typically occurs following repeated low-frequency afferent stimulation, but it can be induced by other methods. Long-term depression appears to play a role in MEMORY.
Endogenous amino acids released by neurons as excitatory neurotransmitters. Glutamic acid is the most common excitatory neurotransmitter in the brain. Aspartic acid has been regarded as an excitatory transmitter for many years, but the extent of its role as a transmitter is unclear.
Inorganic or organic derivatives of phosphinic acid, H2PO(OH). They include phosphinates and phosphinic acid esters.
(2S-(2 alpha,3 beta,4 beta))-2-Carboxy-4-(1-methylethenyl)-3-pyrrolidineacetic acid. Ascaricide obtained from the red alga Digenea simplex. It is a potent excitatory amino acid agonist at some types of excitatory amino acid receptors and has been used to discriminate among receptor types. Like many excitatory amino acid agonists it can cause neurotoxicity and has been used experimentally for that purpose.
Common name for Carassius auratus, a type of carp (CARPS).
A reflex in which the AFFERENT NEURONS synapse directly on the EFFERENT NEURONS, without any INTERCALATED NEURONS. (Lockard, Desk Reference for Neuroscience, 2nd ed.)
Optical imaging techniques used for recording patterns of electrical activity in tissues by monitoring transmembrane potentials via FLUORESCENCE imaging with voltage-sensitive fluorescent dyes.
The smallest difference which can be discriminated between two stimuli or one which is barely above the threshold.
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.
The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.
The synapse between a neuron and a muscle.
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.
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.
Spiny processes on DENDRITES, each of which receives excitatory input from one nerve ending (NERVE ENDINGS). They are commonly found on PURKINJE CELLS and PYRAMIDAL CELLS.
Fishes which generate an electric discharge. The voltage of the discharge varies from weak to strong in various groups of fish. The ELECTRIC ORGAN and electroplax are of prime interest in this group. They occur in more than one family.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
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.
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.
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.
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.
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.
The ability of a substrate to allow the passage of ELECTRONS.
A species of the family Ranidae (true frogs). The only anuran properly referred to by the common name "bullfrog", it is the largest native anuran in North America.
The repeated weak excitation of brain structures, that progressively increases sensitivity to the same stimulation. Over time, this can lower the threshold required to trigger seizures.
Cerebral cortex region on the medial aspect of the PARAHIPPOCAMPAL GYRUS, immediately caudal to the OLFACTORY CORTEX of the uncus. The entorhinal cortex is the origin of the major neural fiber system afferent to the HIPPOCAMPAL FORMATION, the so-called PERFORANT PATHWAY.
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.
A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)
One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
GRAY MATTER located in the dorsomedial part of the MEDULLA OBLONGATA associated with the solitary tract. The solitary nucleus receives inputs from most organ systems including the terminations of the facial, glossopharyngeal, and vagus nerves. It is a major coordinator of AUTONOMIC NERVOUS SYSTEM regulation of cardiovascular, respiratory, gustatory, gastrointestinal, and chemoreceptive aspects of HOMEOSTASIS. The solitary nucleus is also notable for the large number of NEUROTRANSMITTERS which are found therein.
One of the two major classes of cholinergic receptors. Nicotinic receptors were originally distinguished by their preference for NICOTINE over MUSCARINE. They are generally divided into muscle-type and neuronal-type (previously ganglionic) based on pharmacology, and subunit composition of the receptors.
Drugs that bind to nicotinic cholinergic receptors (RECEPTORS, NICOTINIC) and block the actions of acetylcholine or cholinergic agonists. Nicotinic antagonists block synaptic transmission at autonomic ganglia, the skeletal neuromuscular junction, and at central nervous system nicotinic synapses.
The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.
Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.
The action of a drug that may affect the activity, metabolism, or toxicity of another drug.
A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
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.
Cytoskeleton specialization at the cytoplasmic side of postsynaptic membrane in SYNAPSES. It is involved in neuronal signaling and NEURONAL PLASTICITY and comprised of GLUTAMATE RECEPTORS; scaffolding molecules (e.g., PSD95, PSD93), and other proteins (e.g., CaCMKII).
The relationship between the dose of an administered drug and the response of the organism to the drug.
Substances used for their pharmacological actions on glycinergic systems. Glycinergic agents include agonists, antagonists, degradation or uptake inhibitors, depleters, precursors, and modulators of receptor function.
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.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
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.
Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.
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.
Drugs used for their actions on any aspect of excitatory amino acid neurotransmitter systems. Included are drugs that act on excitatory amino acid receptors, affect the life cycle of excitatory amino acid transmitters, or affect the survival of neurons using excitatory amino acids.
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).
A family of hexahydropyridines.
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.
A branched-chain essential amino acid that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
Heterocyclic compounds of a ring with SULFUR and two NITROGEN atoms fused to a BENZENE ring. Members inhibit SODIUM-POTASSIUM-CHLORIDE SYMPORTERS and are used as DIURETICS.
Endogenous compounds and drugs that bind to and activate GABA-B RECEPTORS.
A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.
A major class of calcium-activated potassium channels that are found primarily in excitable CELLS. They play important roles in the transmission of ACTION POTENTIALS and generate a long-lasting hyperpolarization known as the slow afterhyperpolarization.
The brain stem nucleus that receives the central input from the cochlear nerve. The cochlear nucleus is located lateral and dorsolateral to the inferior cerebellar peduncles and is functionally divided into dorsal and ventral parts. It is tonotopically organized, performs the first stage of central auditory processing, and projects (directly or indirectly) to higher auditory areas including the superior olivary nuclei, the medial geniculi, the inferior colliculi, and the auditory cortex.
A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.
A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
Gelatinous-appearing material in the dorsal horn of the spinal cord, consisting chiefly of Golgi type II neurons and some larger nerve cells.
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Physical forces and actions in living things.
An eleven-amino acid neurotransmitter that appears in both the central and peripheral nervous systems. It is involved in transmission of PAIN, causes rapid contractions of the gastrointestinal smooth muscle, and modulates inflammatory and immune responses.
Drugs used to prevent SEIZURES or reduce their severity.
Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.
Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.
Reflex contraction of a muscle in response to stretching, which stimulates muscle proprioceptors.
The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
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.
An enkephalin analog that selectively binds to the MU OPIOID RECEPTOR. It is used as a model for drug permeability experiments.
Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents.
A class of drugs that act by inhibition of sodium influx through cell membranes. Blockade of sodium channels slows the rate and amplitude of initial rapid depolarization, reduces cell excitability, and reduces conduction velocity.
A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.
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.
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.
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.
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.
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.
Drugs that bind to and activate cholinergic receptors.
Neurons in the SPINAL CORD DORSAL HORN whose cell bodies and processes are confined entirely to the CENTRAL NERVOUS SYSTEM. They receive collateral or direct terminations of dorsal root fibers. They send their axons either directly to ANTERIOR HORN CELLS or to the WHITE MATTER ascending and descending longitudinal fibers.
One of the endogenous pentapeptides with morphine-like activity. It differs from LEU-ENKEPHALIN by the amino acid METHIONINE in position 5. Its first four amino acid sequence is identical to the tetrapeptide sequence at the N-terminal of BETA-ENDORPHIN.
A potent noncompetitive antagonist of the NMDA receptor (RECEPTORS, N-METHYL-D-ASPARTATE) used mainly as a research tool. The drug has been considered for the wide variety of neurodegenerative conditions or disorders in which NMDA receptors may play an important role. Its use has been primarily limited to animal and tissue experiments because of its psychotropic effects.
NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.
Computer-based representation of physical systems and phenomena such as chemical processes.
Neurons whose primary neurotransmitter is GAMMA-AMINOBUTYRIC ACID.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Central gray matter surrounding the CEREBRAL AQUEDUCT in the MESENCEPHALON. Physiologically it is probably involved in RAGE reactions, the LORDOSIS REFLEX; FEEDING responses, bladder tonus, and pain.
A subsection of the hippocampus, described by Lorente de No, that is located between the HIPPOCAMPUS CA2 FIELD and the DENTATE GYRUS.
The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.
Catalyzes the ATP-dependent PHOSPHORYLATION of GMP to generate GDP and ADP.
Several groups of nuclei in the thalamus that serve as the major relay centers for sensory impulses in the brain.
Clusters of multipolar neurons surrounded by a capsule of loosely organized CONNECTIVE TISSUE located outside the CENTRAL NERVOUS SYSTEM.
Cell surface proteins that bind amino acids and trigger changes which influence the behavior of cells. Glutamate receptors are the most common receptors for fast excitatory synaptic transmission in the vertebrate central nervous system, and GAMMA-AMINOBUTYRIC ACID and glycine receptors are the most common receptors for fast inhibition.
An agonist at two subsets of excitatory amino acid receptors, ionotropic receptors that directly control membrane channels and metabotropic receptors that indirectly mediate calcium mobilization from intracellular stores. The compound is obtained from the seeds and fruit of Quisqualis chinensis.
Endogenous compounds and drugs that bind to and activate GABA-A RECEPTORS.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.

The functional anatomy of the normal human auditory system: responses to 0.5 and 4.0 kHz tones at varied intensities. (1/5056)

Most functional imaging studies of the auditory system have employed complex stimuli. We used positron emission tomography to map neural responses to 0.5 and 4.0 kHz sine-wave tones presented to the right ear at 30, 50, 70 and 90 dB HL and found activation in a complex neural network of elements traditionally associated with the auditory system as well as non-traditional sites such as the posterior cingulate cortex. Cingulate activity was maximal at low stimulus intensities, suggesting that it may function as a gain control center. In the right temporal lobe, the location of the maximal response varied with the intensity, but not with the frequency of the stimuli. In the left temporal lobe, there was evidence for tonotopic organization: a site lateral to the left primary auditory cortex was activated equally by both tones while a second site in primary auditory cortex was more responsive to the higher frequency. Infratentorial activations were contralateral to the stimulated ear and included the lateral cerebellum, the lateral pontine tegmentum, the midbrain and the medial geniculate. Contrary to predictions based on cochlear membrane mechanics, at each intensity, 4.0 kHz stimuli were more potent activators of the brain than the 0.5 kHz stimuli.  (+info)

Developmental synaptic changes increase the range of integrative capabilities of an identified excitatory neocortical connection. (2/5056)

Excitatory synaptic transmission between pyramidal cells and fast-spiking (FS) interneurons of layer V of the motor cortex was investigated in acute slices by using paired recordings at 30 degrees C combined with morphological analysis. The presynaptic and postsynaptic properties at these identified central synapses were compared between 3- and 5-week-old rats. At these two postnatal developmental stages, unitary EPSCs were mediated by the activation of AMPA receptors with fast kinetics at a holding potential of -72 mV. The amplitude distribution analysis of the EPSCs indicates that, at both stages, pyramidal-FS connections consisted of multiple functional release sites. The apparent quantal size obtained by decreasing the external calcium ([Ca2+]e) varied from 11 to 29 pA near resting membrane potential. In young rats, pairs of presynaptic action potentials elicited unitary synaptic responses that displayed paired-pulse depression at all tested frequencies. In older animals, inputs from different pyramidal cells onto the same FS interneuron had different paired-pulse response characteristics and, at most of these connections, a switch from depression to facilitation occurred when decreasing the rate of presynaptic stimulation. The balance between facilitation and depression endows pyramidal-FS connections from 5-week-old animals with wide integrative capabilities and confers unique functional properties to each synapse.  (+info)

Modulation of long-term synaptic depression in visual cortex by acetylcholine and norepinephrine. (3/5056)

In a slice preparation of rat visual cortex, we discovered that paired-pulse stimulation (PPS) elicits a form of homosynaptic long-term depression (LTD) in the superficial layers when carbachol (CCh) or norepinephrine (NE) is applied concurrently. PPS by itself, or CCh and NE in the absence of synaptic stimulation, produced no lasting change. The LTD induced by PPS in the presence of NE or CCh is of comparable magnitude with that obtained with prolonged low-frequency stimulation (LFS) but requires far fewer stimulation pulses (40 vs 900). The cholinergic facilitation of LTD was blocked by atropine and pirenzepine, suggesting involvement of M1 receptors. The noradrenergic facilitation of LTD was blocked by urapidil and was mimicked by methoxamine, suggesting involvement of alpha1 receptors. beta receptor agonists and antagonists were without effect. Induction of LTD by PPS was inhibited by NMDA receptor blockers (completely in the case of NE; partially in the case of CCh), suggesting that one action of the modulators is to control the gain of NMDA receptor-dependent homosynaptic LTD in visual cortex. We propose that this is a mechanism by which cholinergic and noradrenergic inputs to the neocortex modulate naturally occurring receptive field plasticity.  (+info)

Plasticity of first-order sensory synapses: interactions between homosynaptic long-term potentiation and heterosynaptically evoked dopaminergic potentiation. (4/5056)

Persistent potentiations of the chemical and electrotonic components of the eighth nerve (NVIII) EPSP recorded in vivo in the goldfish reticulospinal neuron, the Mauthner cell, can be evoked by afferent tetanization or local dendritic application of an endogenous transmitter, dopamine (3-hydroxytyramine). These modifications are attributable to the activation of distinct intracellular kinase cascades. Although dopamine-evoked potentiation (DEP) is mediated by the cAMP-dependent protein kinase (PKA), tetanization most likely activates a Ca2+-dependent protein kinase via an increased intracellular Ca2+ concentration. We present evidence that the eighth nerve tetanus that induces LTP does not act by triggering dopamine release, because it is evoked in the presence of a broad spectrum of dopamine antagonists. To test for interactions between these pathways, we applied the potentiating paradigms sequentially. When dopamine was applied first, tetanization produced additional potentiation of the mixed synaptic response, but when the sequence was reversed, DEP was occluded, indicating that the synapses potentiated by the two procedures belong to the same or overlapping populations. Experiments were conducted to determine interactions between the underlying regulatory mechanisms and the level of their convergence. Inhibiting PKA does not impede tetanus-induced LTP, and chelating postsynaptic Ca2+ with BAPTA does not block DEP, indicating that the initial steps of the induction processes are independent. Pharmacological and voltage-clamp analyses indicate that the two pathways converge on functional AMPA/kainate receptors for the chemically mediated EPSP and gap junctions for the electrotonic component or at intermediaries common to both pathways. A cellular model incorporating these interactions is proposed on the basis of differential modulation of synaptic responses via receptor-protein phosphorylation.  (+info)

Activity-dependent metaplasticity of inhibitory and excitatory synaptic transmission in the lamprey spinal cord locomotor network. (5/5056)

Paired intracellular recordings have been used to examine the activity-dependent plasticity and neuromodulator-induced metaplasticity of synaptic inputs from identified inhibitory and excitatory interneurons in the lamprey spinal cord. Trains of spikes at 5-20 Hz were used to mimic the frequency of spiking that occurs in network interneurons during NMDA or brainstem-evoked locomotor activity. Inputs from inhibitory and excitatory interneurons exhibited similar activity-dependent changes, with synaptic depression developing during the spike train. The level of depression reached was greater with lower stimulation frequencies. Significant activity-dependent depression of inputs from excitatory interneurons and inhibitory crossed caudal interneurons, which are central elements in the patterning of network activity, usually developed between the fifth and tenth spikes in the train. Because these interneurons typically fire bursts of up to five spikes during locomotor activity, this activity-dependent plasticity will presumably not contribute to the patterning of network activity. However, in the presence of the neuromodulators substance P and 5-HT, significant activity-dependent metaplasticity of these inputs developed over the first five spikes in the train. Substance P induced significant activity-dependent depression of inhibitory but potentiation of excitatory interneuron inputs, whereas 5-HT induced significant activity-dependent potentiation of both inhibitory and excitatory interneuron inputs. Because these metaplastic effects are consistent with the substance P and 5-HT-induced modulation of the network output, activity-dependent metaplasticity could be a potential mechanism underlying the coordination and modulation of rhythmic network activity.  (+info)

GABAergic excitatory synapses and electrical coupling sustain prolonged discharges in the prey capture neural network of Clione limacina. (6/5056)

Afterdischarges represent a prominent characteristic of the neural network that controls prey capture reactions in the carnivorous mollusc Clione limacina. Their main functional implication is transformation of a brief sensory input from a prey into a lasting prey capture response. The present study, which focuses on the neuronal mechanisms of afterdischarges, demonstrates that a single pair of interneurons [cerebral A interneuron (Cr-Aint)] is responsible for afterdischarge generation in the network. Cr-Aint neurons are electrically coupled to all other neurons in the network and produce slow excitatory synaptic inputs to them. This excitatory transmission is found to be GABAergic, which is demonstrated by the use of GABA antagonists, uptake inhibitors, and double-labeling experiments showing that Cr-Aint neurons are GABA-immunoreactive. The Cr-Aint neurons organize three different pathways in the prey capture network, which provide positive feedback necessary for sustaining prolonged spike activity. The first pathway includes electrical coupling and slow chemical transmission from the Cr-Aint neurons to all other neurons in the network. The second feedback is based on excitatory reciprocal connections between contralateral interneurons. Recurrent excitation via the contralateral cell can sustain prolonged interneuron firing, which then drives the activity of all other cells in the network. The third positive feedback is represented by prominent afterdepolarizing potentials after individual spikes in the Cr-Aint neurons. Afterdepolarizations apparently represent recurrent GABAergic excitatory inputs. It is suggested here that these afterdepolarizing potentials are produced by GABAergic excitatory autapses.  (+info)

Comparative effects of methylmercury on parallel-fiber and climbing-fiber responses of rat cerebellar slices. (7/5056)

The environmental neurotoxicant methylmercury (MeHg) causes profound disruption of cerebellar function. Previous studies have shown that acute exposure to MeHg impairs synaptic transmission in both the peripheral and central nervous systems. However, the effects of MeHg on cerebellar synaptic function have never been examined. In the present study, effects of acute exposure to MeHg on synaptic transmission between parallel fibers or climbing fibers and Purkinje cells were compared in 300- to 350-microm cerebellar slices by using extracellular and intracellular microelectrode-recording techniques. Field potentials of parallel-fiber volleys (PFVs) and the associated postsynaptic responses (PSRs) were recorded in the molecular layer by stimulating the parallel fibers in transverse cerebellar slices. The climbing-fiber responses were also recorded in the molecular layer by stimulating white matter in sagittal cerebellar slices. At 20, 100, and 500 microM, MeHg reduced the amplitude of both PFVs and the associated PSRs to complete block, however, it blocked PSRs more rapidly than PFVs. MeHg also decreased the amplitudes of climbing-fiber responses to complete block. For all responses, an initial increase in amplitude preceded MeHg-induced suppression. Intracellular recordings of excitatory postsynaptic potentials of Purkinje cells were compared before and after MeHg. At 100 microM and 20 microM, MeHg blocked the Na+-dependent, fast somatic spikes and Ca++-dependent, slow dendritic spike bursts. MeHg also hyperpolarized and then depolarized Purkinje cell membranes, suppressed current conduction from parallel fibers or climbing fibers to dendrites of Purkinje cells, and blocked synaptically activated local responses. MeHg switched the pattern of repetitive firing of Purkinje cells generated spontaneously or by depolarizing current injection at Purkinje cell soma from predominantly Na+-dependent, fast somatic spikes to predominantly Ca++-dependent, low amplitude, slow dendritic spike bursts. Thus, acute exposure to MeHg causes a complex pattern of effects on cerebellar synaptic transmission, with apparent actions on both neuronal excitability and chemical synaptic transmission.  (+info)

Receptor mechanisms underlying heterogenic reflexes among the triceps surae muscles of the cat. (8/5056)

The soleus (S), medial gastrocnemius (MG), and lateral gastrocnemius (LG) muscles of the cat are interlinked by rapid spinal reflex pathways. In the decerebrate state, these heterogenic reflexes are either excitatory and length dependent or inhibitory and force dependent. Mechanographic analysis was used to obtain additional evidence that the muscle spindle primary ending and the Golgi tendon organ provide the major contributions to these reflexes, respectively. The tendons of the triceps surae muscles were separated and connected to independent force transducers and servo-controlled torque motors in unanesthetized, decerebrate cats. The muscles were activated as a group using crossed-extension reflexes. Electrical stimulation of the caudal cutaneous sural nerve was used to provide a particularly strong activation of MG and decouple the forces of the triceps surae muscles. During either form of activation, the muscles were stretched either individually or in various combinations to determine the strength and characteristics of autogenic and heterogenic feedback. The corresponding force responses, including both active and passive components, were measured during the changing background tension. During activation of the entire group, the excitatory, heterogenic feedback linking the three muscles was found to be strongest onto LG and weakest onto MG, in agreement with previous results concerning the strengths of heteronymous Ia excitatory postsynaptic potentials among the triceps surae muscles. The inhibition, which is known to affect only the soleus muscle, was dependent on active contractile force and was detected essentially as rapidly as length dependent excitation. The inhibition outlasted the excitation and was blocked by intravenous strychnine. These results indicate that the excitatory and inhibitory effects are dominated by feedback from primary spindle receptors and Golgi tendon organs. The interactions between these two feedback pathways potentially can influence both the mechanical coupling between ankle and knee.  (+info)

The term "decerebrate" comes from the Latin word "cerebrum," which means brain. In this context, the term refers to a state where the brain is significantly damaged or absent, leading to a loss of consciousness and other cognitive functions.

Some common symptoms of the decerebrate state include:

* Loss of consciousness
* Flaccid paralysis (loss of muscle tone)
* Dilated pupils
* Lack of responsiveness to stimuli
* Poor or absent reflexes
* Inability to speak or communicate

The decerebrate state can be caused by a variety of factors, including:

* Severe head injury
* Stroke or cerebral vasculature disorders
* Brain tumors or cysts
* Infections such as meningitis or encephalitis
* Traumatic brain injury

Treatment for the decerebrate state is typically focused on addressing the underlying cause of the condition. This may involve medications to control seizures, antibiotics for infections, or surgery to relieve pressure on the brain. In some cases, the decerebrate state may be a permanent condition, and individuals may require long-term care and support.

There are many different types of epilepsy, each with its own unique set of symptoms and characteristics. Some common forms of epilepsy include:

1. Generalized Epilepsy: This type of epilepsy affects both sides of the brain and can cause a range of seizure types, including absence seizures, tonic-clonic seizures, and atypical absence seizures.
2. Focal Epilepsy: This type of epilepsy affects only one part of the brain and can cause seizures that are localized to that area. There are several subtypes of focal epilepsy, including partial seizures with complex symptoms and simple partial seizures.
3. Tonic-Clonic Epilepsy: This type of epilepsy is also known as grand mal seizures and can cause a loss of consciousness, convulsions, and muscle stiffness.
4. Lennox-Gastaut Syndrome: This is a rare and severe form of epilepsy that typically develops in early childhood and can cause multiple types of seizures, including tonic, atonic, and myoclonic seizures.
5. Dravet Syndrome: This is a rare genetic form of epilepsy that typically develops in infancy and can cause severe, frequent seizures.
6. Rubinstein-Taybi Syndrome: This is a rare genetic disorder that can cause intellectual disability, developmental delays, and various types of seizures.
7. Other forms of epilepsy include Absence Epilepsy, Myoclonic Epilepsy, and Atonic Epilepsy.

The symptoms of epilepsy can vary widely depending on the type of seizure disorder and the individual affected. Some common symptoms of epilepsy include:

1. Seizures: This is the most obvious symptom of epilepsy and can range from mild to severe.
2. Loss of consciousness: Some people with epilepsy may experience a loss of consciousness during a seizure, while others may remain aware of their surroundings.
3. Confusion and disorientation: After a seizure, some people with epilepsy may feel confused and disoriented.
4. Memory loss: Seizures can cause short-term or long-term memory loss.
5. Fatigue: Epilepsy can cause extreme fatigue, both during and after a seizure.
6. Emotional changes: Some people with epilepsy may experience emotional changes, such as anxiety, depression, or mood swings.
7. Cognitive changes: Epilepsy can affect cognitive function, including attention, memory, and learning.
8. Sleep disturbances: Some people with epilepsy may experience sleep disturbances, such as insomnia or sleepiness.
9. Physical symptoms: Depending on the type of seizure, people with epilepsy may experience physical symptoms such as muscle weakness, numbness or tingling, and sensory changes.
10. Social isolation: Epilepsy can cause social isolation due to fear of having a seizure in public or stigma associated with the condition.

It's important to note that not everyone with epilepsy will experience all of these symptoms, and some people may have different symptoms depending on the type of seizure they experience. Additionally, some people with epilepsy may experience additional symptoms not listed here.

There are many different types of seizures, each with its own unique set of symptoms. Some common types of seizures include:

1. Generalized seizures: These seizures affect both sides of the brain and can cause a range of symptoms, including convulsions, loss of consciousness, and muscle stiffness.
2. Focal seizures: These seizures affect only one part of the brain and can cause more specific symptoms, such as weakness or numbness in a limb, or changes in sensation or vision.
3. Tonic-clonic seizures: These seizures are also known as grand mal seizures and can cause convulsions, loss of consciousness, and muscle stiffness.
4. Absence seizures: These seizures are also known as petit mal seizures and can cause a brief loss of consciousness or staring spell.
5. Myoclonic seizures: These seizures can cause sudden, brief muscle jerks or twitches.
6. Atonic seizures: These seizures can cause a sudden loss of muscle tone, which can lead to falls or drops.
7. Lennox-Gastaut syndrome: This is a rare and severe form of epilepsy that can cause multiple types of seizures, including tonic, atonic, and myoclonic seizures.

Seizures can be diagnosed through a combination of medical history, physical examination, and diagnostic tests such as electroencephalography (EEG) or imaging studies. Treatment for seizures usually involves anticonvulsant medications, but in some cases, surgery or other interventions may be necessary.

Overall, seizures are a complex and multifaceted symptom that can have a significant impact on an individual's quality of life. It is important to seek medical attention if you or someone you know is experiencing seizures, as early diagnosis and treatment can help to improve outcomes and reduce the risk of complications.

In neuroscience, an excitatory postsynaptic potential (EPSP) is a postsynaptic potential that makes the postsynaptic neuron ... generating an excitatory postsynaptic current. This depolarizing current causes an increase in membrane potential, the EPSP. ... The flow of ions that causes an EPSP is an excitatory postsynaptic current (EPSC). EPSPs, like IPSPs, are graded (i.e. they ... These are the opposite of inhibitory postsynaptic potentials (IPSPs), which usually result from the flow of negative ions into ...
... the postsynaptic cell will be more likely to generate an action potential and an excitatory postsynaptic potential will occur ( ... This phenomenon is known as an excitatory postsynaptic potential (EPSP). It may occur via direct contact between cells (i.e., ... an inhibitory postsynaptic potential will occur (IPSP). Although the receptors at an excitatory synapse strive to bring the ... "Excitatory and Inhibitory Postsynaptic Potentials". Sinauer Associates, Inc. {{cite journal}}: Cite journal requires ,journal ...
Excitatory post-synaptic potentials (EPSPs) depolarize the membrane and move the potential closer to the threshold for an ... This is the case for both excitatory and inhibitory postsynaptic potentials. Synaptic potentials are not static. The concept of ... decreasing the likelihood of an action potential occurring. The Excitatory Post Synaptic potential is most likely going to be ... Synaptic potential refers to the potential difference across the postsynaptic membrane that results from the action of ...
... generates fast excitatory postsynaptic potentials (EPSP). AMPA activates AMPA receptors that are non-selective cationic ... channels allowing the passage of Na+ and K+ and therefore have an equilibrium potential near 0 mV. AMPA was first synthesized, ...
In excitatory postsynaptic potentials, an excitatory response is generated. This is caused by an excitatory neurotransmitter, ... This neurotransmitter causes an inhibitory postsynaptic potential in the postsynaptic neuron. This response will cause the ... If a graded potential is strong enough, or if several graded potentials occur in a fast enough frequency, the depolarization is ... In response to stimuli, the sensory receptor initiates sensory transduction by creating graded potentials or action potentials ...
"Gamma-Hydroxybutyrate inhibits excitatory postsynaptic potentials in rat hippocampal slices". European Journal of Pharmacology ... Potential treatment modalities into biochemical and neurological correction should aim to reduce one or both while not ... This disruption has the potential to impair glutamate homeostasis and may lead to uncoupling of the normal balance between ... simultaneously releasing excitatory neurotransmitters onto motor neurons. Because the number and function of GABAB receptors ...
This kind of memory serves as surrogate of the excitatory postsynaptic potential. The model has a threshold N t h {\ ... denotes magnitude of excitatory postsynaptic potential at moment t {\displaystyle t} ; t k {\displaystyle t_{k}} - is the ... The location of the step is controlled by the level of inhibition potential, see Fig. 1. Due to this type of dependence, the H- ... The BN concept originated in 1996 and 1998 papers by A. K. Vidybida, For a generic neuron the stimuli are excitatory impulses. ...
Aghajanian, G. K; Marek, G. J (1 April 1997). "Serotonin Induces Excitatory Postsynaptic Potentials in Apical Dendrites of ... produces an increase in the frequency and amplitude of spontaneous excitatory postsynaptic potentials in layer V pyramidal ... Ronald S. Duman and George K. Aghajanian: Synaptic Dysfunction in Depression: Potential Therapeutic Targets. Science. "George ... Duman, Ronald S.; Aghajanian, George K. (5 October 2012). "Synaptic Dysfunction in Depression: Potential Therapeutic Targets". ...
Electrotonic potentials that increase the membrane potential are called excitatory postsynaptic potentials (EPSPs). This is ... Electrotonic potentials which decrease the membrane potential are called inhibitory postsynaptic potentials (IPSPs). They ... However, all action potentials are begun by electrotonic potentials depolarizing the membrane above the threshold potential ... Neurons and other excitable cells produce two types of electrical potential: Electrotonic potential (or graded potential), a ...
The AMPA receptor (AMPAR) is the engine that drives excitatory postsynaptic potentials (EPSPs). While some forms of the AMPAR ... the reversal potential of the EPSP current is roughly 0 mV). However, the postsynaptic membrane potential will not change by ... As such, it also spans the electric field generated by the membrane potential. The magnesium binding site within the NMDAR ... This synaptic summation drives the membrane potential toward values that could not be reached with single synaptic stimuli. As ...
The opposite of an inhibitory postsynaptic potential is an excitatory postsynaptic potential (EPSP), which is a synaptic ... Glutamate, an excitatory neurotransmitter, is usually associated with excitatory postsynaptic potentials in synaptic ... An inhibitory postsynaptic potential (IPSP) is a kind of synaptic potential that makes a postsynaptic neuron less likely to ... An electric current that changes the postsynaptic membrane potential to create a more negative postsynaptic potential is ...
Action potentials are most commonly initiated by excitatory postsynaptic potentials from a presynaptic neuron. Typically, ... The action potential in a normal skeletal muscle cell is similar to the action potential in neurons. Action potentials result ... This all-or-nothing property of the action potential sets it apart from graded potentials such as receptor potentials, ... In contrast to passive spread of electric potentials (electrotonic potential), action potentials are generated anew along ...
These neurons displayed a higher frequency and larger amplitudes of miniature excitatory postsynaptic potentials (mEPSP). Mice ... SynGAP1 is shown to localize at the postsynaptic density on the dendritic spines of excitatory synapses. Cultured neurons of ... Jaffe H, Vinade L, Dosemeci A (August 2004). "Identification of novel phosphorylation sites on postsynaptic density proteins". ...
alpha-1 adrenergic receptor activation, by norepinephrine, decreases glutamatergic excitatory postsynaptic potentials at AMPA ... The field potentials measured for artificially stimulated CDC were eventually much stronger than that of a normal hearing cat. ... An evoked response study of congenitally deaf kittens used local field potentials to measure cortical plasticity in the ... "Preservation of Auditory P300-Like Potentials in Cortical Deafness". PLOS ONE. 7 (1): e29909. Bibcode:2012PLoSO...729909C. doi: ...
In particular, norepinephrine decreases glutamatergic excitatory postsynaptic potentials by the activation of α1-adrenergic ... ISBN 978-0-87893-725-7. Chou EC, Capello SA, Levin RM, Longhurst PA (December 2003). "Excitatory alpha1-adrenergic receptors ...
This causes a depolarization, and results in an excitatory post-synaptic potential. Thus, ACh is excitatory on skeletal muscle ... When a motor neuron generates an action potential, it travels rapidly along the nerve until it reaches the neuromuscular ... Their effect on target cells is usually excitatory. The M2 and M4 subtypes are Gi/Go-coupled; they decrease intracellular ...
An excitatory postsynaptic potential (EPSP) opens the channels, thus generating a LTS. The LTS triggers Na+-dependent action ... such as excitatory postsynaptic potentials (EPSP). LTS were discovered by Rodolfo Llinás and coworkers in the 1980s. ... LTS are often triggered after an inhibitory postsynaptic potential (IPSP) due to the fast recovery of T-type calcium channels ... As with the action potentials that follow them, LTS vary little in amplitude or shape at different holding potentials. This ...
Stimulation of aberrant mossy fibre areas increases the excitatory postsynaptic potential response. However, aberrant mossy ... It has been found that GABA reversal potential is depolarising in the subpopulation of the pyramidal cells due to the lack of ... They project into the hilus of the dentate gyrus and stratum lucidum in the CA3 region giving inputs to both excitatory and ... Loss of mossy cells lowers the threshold of action potentials of the granule cells. In certain patients with temporal lobe ...
Kainate receptors likely control a sodium channel that produces excitatory postsynaptic potentials (EPSPs) when glutamate binds ... Moloney, Mark G. (1998). "Excitatory amino acids". Natural Product Reports. 15 (2): 205-219. doi:10.1039/a815205y. PMID 9586226 ... the principal excitatory neurotransmitter in the central nervous system. Glutamate is produced by the cell's metabolic ... slice preparation to study the physiological effect of excitotoxicity and assess the neuroprotective capabilities of potential ...
Kanda K, Takano K (February 1983). "Effect of tetanus toxin on the excitatory and the inhibitory post-synaptic potentials in ... The action of the A-chain also stops the affected neurons from releasing excitatory transmitters, by degrading the protein ...
Increased NT-3/trkC binding results in larger monosynaptic excitatory postsynaptic potentials (EPSPs) and reduced polysynaptic ... reducing the size of monosynaptic excitatory postsynaptic potentials (EPSPs) and increasing polysynaptic signaling. In the ... In other cases, such as neuroblastoma Trk A acts as a promising prognostic indicator as it has the potential to induce terminal ... Aloe L, Rocco ML, Bianchi P, Manni L (November 2012). "Nerve growth factor: from the early discoveries to the potential ...
"The involvement of adenosine neuromodulation in pentobarbital-induced field excitatory postsynaptic potentials depression in ... Boissard CG, Gribkoff VK (1993). "The effects of the adenosine reuptake inhibitor soluflazine on synaptic potentials and ... on extracellular purines and excitatory amino acids in CA1 of rat hippocampus during transient ischaemia". Br J Pharmacol. 100 ... barbiturates and propofol of excitatory synaptic transmissions mediated by adenosine neuromodulation]". Masui. 55 (6): 684-691 ...
Transduction (biophysics) EPSP (excitatory post-synaptic potential) IPSP (inhibitory post-synaptic potential) Hikosaka, R; ... For the interneurons exhibiting one-way signaling, they would receive an excitatory stimulus, experimentally, and the post- ... The change from a cell that can generate action potentials to solely functioning off of a graded potential is drastic, and may ... These neurons use a graded potential to transmit data as they lack the membrane potential that spiking neurons possess. This ...
Excitatory and inhibitory synaptic transmission is realized mostly by excitatory postsynaptic potentials (EPSPs), and ... strongly on the relative timing of the onset of the excitatory postsynaptic potential and the postsynaptic action potential. ... potentials at the post-synaptic membrane will summate in the cell body). Later models also provided for excitatory and ... One principle by which neurons work is neural summation - potentials at the postsynaptic membrane will sum up in the cell body ...
Receptors in groups II and III reduce the activity of postsynaptic potentials, both excitatory and inhibitory, in the cortex. ... These receptors are involved in presynaptic inhibition, and do not appear to affect postsynaptic membrane potential by ... but they also increase inhibitory postsynaptic potentials, or IPSPs. They can also inhibit glutamate release and can modulate ... For example, one study found that Group I mGluRs are located mostly on postsynaptic parts of cells, while groups II and III are ...
Electrical stimuli to the auditory nerve evoke a graded excitatory postsynaptic potential in the octopus cells. These EPSPs are ... excitatory and inhibitory input through the outermost molecular layer and the basal dendrites receiving excitatory and ... Excitatory acoustic input comes from auditory nerve fibers and also from stellate cells of the VCN. Acoustic input is also ... They are also called chopper cells, in reference to their ability to fire a regularly spaced train of action potentials for the ...
... is a form of postsynaptic potential inhibition that can be represented mathematically as reducing the excitatory potential by ... The amplitude of subsequent excitatory postsynaptic potential (EPSP) is reduced by this, in accordance with Ohm's Law. This ... at least on subthreshold postsynaptic potentials. In a 2005 article, researchers Abbott and Chance state that "Although the ... simple scenario arises if the inhibitory synaptic reversal potential is identical to the resting potential.[citation needed] ...
The excitatory postsynaptic potential (EPSP) produced by activation of an NMDA receptor also increases the concentration of ... Therefore, NMDA receptors will only open if glutamate is in the synapse and concurrently the postsynaptic membrane is already ...
... they can be classified as a type of field excitatory postsynaptic potentials. In some areas of the brain, such as the ... In neuroscience, a population spike (PS) is the shift in electrical potential as a consequence of the movement of ions involved ... Because these neurons are in the same orientation, the extracellular signals from the generation of action potentials don't ... The first interpretations of hippocampal field potentials were developed by Per Andersen. McNaughton, B. L.; Douglas, R. M.; ...
... as the potential comes closer to zero. This is an excitatory postsynaptic potential (EPSP), as it brings the neuron's potential ... Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Postsynaptic ... their postsynaptic potentials add together. If the cell is receiving two excitatory postsynaptic potentials, they combine so ... If the cell is receiving both inhibitory and excitatory postsynaptic potentials, they can cancel out, or one can be stronger ...
In CS pacemakers, NE increases only the amplitude of the depolarizing drive potential and the number of action potentials ... This is due to the reduction of excitatory synaptic transmission in a nucleus and increased excitability in motor neurons ... P/Q-type calcium channels are mainly responsible for the release of neurotransmitters that excite, or activate, postsynaptic ... which allows neurons to intrinsically fire action potentials at sub-threshold membrane potentials. Studies have shown that the ...
Long-term changes in a neuron or synapse, resulting in a permanent change in a neuron's excitatory properties can cause ... The neurotransmitters are released by the synapse to propagate the signal to the postsynaptic cell. It has also been ... It has previously been shown that repeated short trains of action potentials causes an exponential decay of the synaptic ... Although now synaptic fatigue is thought to primarily be a presynaptic phenomenon, could postsynaptic processes account for a ...
... their null direction with a simultaneous small excitatory postsynaptic potential and a large inhibitory postsynaptic potential ... The DS ganglion cells respond to their preferred direction with a large excitatory postsynaptic potential followed by a small ... chloride-ion equilibrium potential relative to the resting potential while others have a negative equilibrium potential. This ... Such postsynaptic models are unparsimonious, and so if any given starburst amacrine cells conveys motion information to retinal ...
S(-) form of barbiturate have shown more depressant activity while the R(+) isomers have an excitatory effect. According to ... Perrais D, Ropert N (Jan 1999). "Effect of zolpidem on miniature IPSCs and occupancy of postsynaptic GABAA receptors in central ... Rudolph U, Knoflach F (Sep 2011). "Beyond classical benzodiazepines: novel therapeutic potential of GABAA receptor subtypes". ... Benzodiazepines enhance the receptor affinity for GABA by increasing the decay of spontaneous miniature inhibitory postsynaptic ...
A number of substance-induced psychoses have the potential to transition to schizophrenia, most notably cannabis-induced ... This study further supported genetic involvement for excitatory neurotransmission. Several studies have suggested a genetic ... those of the neuregulin post-synaptic receptor. The result showed that although the mice mostly developed normally, on further ... 2015). "Novel Findings from CNVs Implicate Inhibitory and Excitatory Signaling Complexes in Schizophrenia". Neuron. 86 (5): ...
These random potentials have similar time courses as excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic ... Noise is observed as changes in the membrane potential of a cell. The change in potential causes the accuracy of a neuron to be ... This occurs in the background of a cell when potentials are produced without the nerve stimulation of an action potential, and ... In an action potential, calcium channels are opened by depolarization and release Ca2+ ions into the presynaptic cell. This ...
GABA is then packed and released into the post-synaptic terminals of neurons after synthesis. GABA can also be used to form ... Glutamate is considered an excitatory neurotransmitter, while GABA is an inhibitory neurotransmitter. Glutamate and GABA ... ion is required to offset the positive charge of the Na+ in order to maintain the proper membrane potential. Occluded-out. Once ...
In the brain, excitatory amino acid transporters are crucial in terminating the postsynaptic action of the neurotransmitter ... potential role in dicarboxylic aminoaciduria and neurodegenerative disorders". Genomics. 20 (2): 335-6. doi:10.1006/geno. ... Excitatory amino acid transporter 3 (EAAT3), is a protein that in humans is encoded by the SLC1A1 gene. EAAT3 is expressed on ... Excitatory amino acid transporter 3 is a member of the high-affinity glutamate transporters which plays an essential role in ...
These inputs include inhibitory postsynaptic potentials (IPSPs) and excitatory postsynaptic potentials (EPSPs), meaning that ...
... by action potentials through a completely different mechanism than when Npas4 is induced by excitatory postsynaptic potentials ... While both action potential induced and EPSP induced Npas4 yield Npas4 heterodimers, these heterodimers remarkably have ... Bloodgood, B.L., and Sabatini B.L. (2008). Regulation of synaptic signaling by postsynaptic, non-glutamate receptor ion ... the distribution of inhibitory synapses onto hippocampal neurons restricting information output while increasing the potential ...
... but has no significant influence on GABAergic inhibitory postsynaptic potentials in hippocampal slices. Interaction with ... the pharmacological activity profiles of the two losigamone enantiomers are not identical and suggest further that excitatory ...
Postsynaptic neurons remove little glutamate from the synapse. There is active reuptake into presynaptic neurons, but this ... Once the vesicle is released, glutamate is removed from the synaptic cleft by excitatory amino-acid transporters (EAATs). This ... Current research into autism also indicates potential roles for glutamate, glutamine, and/or GABA in autistic spectrum ... Glutamate residing in the synapse must be rapidly removed in one of three ways: uptake into the postsynaptic compartment, re- ...
Many neurons in the rat and mouse hippocampus respond as place cells: that is, they fire bursts of action potentials when the ... Basket cells in CA3 receive excitatory input from the pyramidal cells and then give an inhibitory feedback to the pyramidal ... Sharp waves in Hebbian theory are seen as persistently repeated stimulations by presynaptic cells, of postsynaptic cells that ... This recurrent inhibition is a simple feedback circuit that can dampen excitatory responses in the hippocampus. The pyramidal ...
It is an excitatory neurotransmitter. This is due to the fact that chloride has a more positive equilibrium potential in early ... A decreased postsynaptic voltage results in a decreased transmission of neurotransmitters. In developing embryos, glycine has ... The efflux of chloride causes the membrane potential to become more positive, or depolarized. As the cells mature, the K+-Cl- ... In addition to this hyperpolarization which decreases the likelihood of action potential propagation, glycine is also ...
... and in particular post-synaptic potentials (see Inhibitory postsynaptic current and Excitatory postsynaptic potential) in the ... Bonmassar G; Anami K; Ives JR; Belliveau JW) (1999). "Visual evoked potential (VEP) measured by simultaneous 64-Channel EEG and ... The simultaneous acquisition of EEG and fMRI data of sufficient quality requires solutions to problems linked to potential ...
When the graded excitatory postsynaptic potentials (EPSPs) depolarize the soma to spike threshold at the axon hillock, first, ... Instead, only when the soma depolarizes enough from accumulating graded potentials and firing an axonal action potential will ... backpropagation can serve as the means of depolarization of the postsynaptic cell. Backpropagating action potentials can induce ... An action potential occurs in the axon first as research illustrates that sodium channels at the dendrites exhibit a higher ...
... the motor neuron innervating the quadriceps produced a small excitatory postsynaptic potential (EPSP). When a similar current ... an inhibitory postsynaptic potential (IPSP) is produced in the quadriceps motor neuron. Although a single EPSP was not enough ... to fire an action potential in the motor neuron, the sum of several EPSPs from multiple sensory neurons synapsing onto the ...
... in chromatolytic motor neurons is the significant reduction in size of the monosynaptic excitatory postsynaptic potentials ( ... This functional change to the anterior horn neurons could result in the elimination of certain excitatory synaptic inputs and ... then potential therapies could be developed for halting the chromatolytic response of neurons and ameliorating the detrimental ...
... or delay in propagation of action potentials or excitatory postsynaptic potentials, can be variable. Every excitatory ... results in specific changes in the integration of excitatory postsynaptic potentials and inhibitory postsynaptic potentials. ... of an action potential depends on the integration of all the incoming excitatory and inhibitory postsynaptic potentials ... the response of the excitatory postsynaptic potential through neurotransmitter release and augmentation of the action potential ...
In the brain the α1 receptors produce a slow depolarizing (excitatory) effect on the postsynaptic membrane, while α2 receptors ... The androgenic nerve fibre when myelinated increases the speed of transmission for an action potential across the length of the ... Both types of β receptors increase the responsiveness of the postsynaptic neuron to its excitatory inputs, which presumably ... Adrenergic receptors can produce both excitatory and inhibitory effects. In general, the behavioral effects of the release of ...
Gasser HS, Graham HT (January 1933). "Potentials produced in the spinal cord by stimulation of dorsal roots". American Journal ... Frank K, Fuortes MG (1957). "Presynaptic and Postsynaptic inhibition of monsynaptic reflexes". Federation Proceedings. 16: 39- ... onto a variety of downstream targets including both excitatory neurons and inhibitory neurons. Synapses between primary ... Barron DH, Matthews BH (April 1938). "The interpretation of potential changes in the spinal cord". The Journal of Physiology. ...
There is potential for confusion because there are different numbering systems used to describe the position of this double ... They are, in effect, released from the postsynaptic cell and act on the presynaptic cell, where the target receptors are ... On the converse, when release of the excitatory neurotransmitter glutamate is reduced, the net effect is a decrease in the ... This endocannabinoid-mediated system permits the postsynaptic cell to control its own incoming synaptic traffic. The ultimate ...
However, postsynaptic induction combined with presynaptic expression requires that, following induction, the postsynaptic cell ... Kato K, Clark GD, Bazan NG, Zorumski CF (January 1994). "Platelet-activating factor as a potential retrograde messenger in CA1 ... The activation of endocannabinoids results in the release of particular neurotransmitters at the excitatory and inhibitory ... Because normal synaptic transmission occurs in a presynaptic to postsynaptic direction, postsynaptic to presynaptic ...
Mossy fibers make an excitatory connection onto granule cells which cause the granule cell to fire an action potential. The ... The nature of the calcium signals that control the presynaptic and postsynaptic function of the olfactory bulb granule cells ... This connection is excitatory as glutamate is released. The parallel fibers and ascending axon synapses from the same granule ... There are two types of excitatory inputs received by GABAergic granule cells; those activated by an AMPA receptor and those ...
"Inward rectifier K+ channel Kir2.3 is localized at the postsynaptic membrane of excitatory synapses". Am. J. Physiol., Cell ... Butz S, Okamoto M, Südhof TC (1998). "A tripartite protein complex with the potential to couple synaptic vesicle exocytosis to ... A family of PSD-95/SAP90-associated proteins localized at postsynaptic density". J. Biol. Chem. 272 (18): 11943-51. doi:10.1074 ... 1996). "SAP102, a novel postsynaptic protein that interacts with NMDA receptor complexes in vivo". Neuron. 17 (2): 255-65. doi: ...
Excitatory synapses increase probability of firing an action potential in the postsynaptic neuron and are often glutamatergic, ... Inhibitory synapses decrease probability of firing an action potential in the postsynaptic neuron and are often GABAergic, in ... Neuroligins interact with other postsynaptic proteins to localize neurotransmitter receptors and channels in the postsynaptic ... Also, overexpression of PSD-95 redirects neuroligin-2 from excitatory to inhibitory synapses, strengthening excitatory input ...
The excitatory postsynaptic potential (EPSP) produced by activation of an NMDA receptor increases the concentration of Ca2+ in ... In a resting-membrane potential, the NMDA receptor pore is opened allowing for an influx of external magnesium ions binding to ... Removal of D-serine can block NMDA-mediated excitatory neurotransmission in many areas. Recently, it has been shown that D- ... Unlike many other NO donors, alkyl nitrates do not have potential NO associated neurotoxic effects. Alkyl nitrates donate NO in ...
Action Potentials / physiology * Animals * Excitatory Postsynaptic Potentials / physiology * Patch-Clamp Techniques * ... We characterized the functional excitatory local input to these 3 cell subtypes in rat primary visual cortex using laser- ... to infer the proportion of shared input based on the occurrence of simultaneous synaptic potentials. Tall pairs of matched type ... We characterized the functional excitatory local in … ...
1978) Quantal analysis of size of excitatory post-synaptic potentials at synapses between hair cells and afferent nerve-fibers ... A silver electrode was placed near the round window to measure the compound action potential in response to click stimuli as an ... Postsynaptic mechanisms such as receptor desensitization also contribute to firing rate adaptation (Goutman and Glowatzki, 2007 ... site for the adaptation mechanism given the wide diversity of neuromodulatory mechanisms on both presynaptic and postsynaptic ...
Selective activation of BK channels in small-headed dendritic spines suppresses excitatory postsynaptic potentials.. Tazerart S ... Intracortical synaptic potential modulation by presynaptic somatic potential (Shu et al. 2006, 2007) References: Shu Y, Duque A ... intracortical synaptic potentials by presynaptic somatic membrane. potential. Nature 441: 761-765.. I opened the Files tab ... Altered integration of excitatory inputs onto the basal dendrites of layer 5 pyramidal neurons in a mouse model of Fragile X ...
... membrane potential increases as the neuron becomes more depolarized by the summation of the excitatory postsynaptic potentials ... Glutamate is the major excitatory neurotransmitter in the brain. The release of glutamate causes an EPSP in the postsynaptic ... The reversal potential of chloride is about negative 70 mV. The contribution of chloride channels during resting potential in ... These channels make it difficult to achieve the threshold membrane potential necessary for an action potential. The influence ...
... long-lasting increase in the slope of the field excitatory postsynaptic potential (fEPSP) at 30 min (35.0 ± 5.6%; mean ± s.e.m ... To infer the potential function of the DNA transposon, LINE, LTR, and SINE elements in LTP, we correlated their profiles with ... B) Classification of all differentially expressed novel lncRNA with a coding potential less than zero (Antisense: overlapping a ... Our analysis revealed 22 lncRNAs to be highly correlated to their neighboring DE protein-coding gene, indicating potential ...
... and reformulated in terms of postsynaptic excitatory and inhibitory potentials by Sir John Eccles and others, using such ... By 1925, in "Remarks on Some Aspects of Reflex Inhibition," he was ready to state his concept of central excitatory and ... Sherringtons work on central excitatory and inhibitory states and the motor unit were the culmination, for him, of the ... Three fundamental publications of the Oxford period were Sherringtons papers on the stretch reflex (1924), central excitatory ...
Polysynaptic excitatory postsynaptic potentials that trigger spasms after spinal cord injury in rats are inhibited by 5-HT1B ... Peripheral serotonin receptor 2B and transient receptor potential channel 4 mediate pruritus to serotonergic antidepressants in ...
Excitatory Postsynaptic Potentials 76% * Interneurons 69% 5 Scopus citations * The Effects of Mild Traumatic Brain Injury, Post ...
... a small voltage change in the downstream neuron known as an excitatory postsynaptic potential (EPSP). A number of such inputs ... Previously ineffective postsynaptic channels can also be brought on line, augmenting the effect of a standard dose of ... Release of neurotransmitter happens when a brief electrical impulse (also known as a spike or action potential) is sent from ... In general, you can think of the pyramidal neurons as the excitatory ones, and the stellates as the inhibitory ones. ...
Excitatory Postsynaptic Potential 20% * Parents decisions about starting and ending a meal for their child during infancy, ... Understanding the potential and pitfalls of digital phenotypes to measure population mental health and wellbeing. Maggio, V., ... Effects of body mass index on the human plasma proteome-potential drivers of obesity-related cardiovascular disease?. ...
Excitatory Postsynaptic Potentials 100% * Neurons 52% * Membranes 51% * Ganglia 35% * Nicotinic Receptors 27% ...
Excitatory Postsynaptic Potential Postsynaptic Potential, Excitatory Postsynaptic Potentials, Excitatory Potential, Excitatory ... Postsynaptic Currents, Excitatory. Postsynaptic Potential, Excitatory. Postsynaptic Potentials, Excitatory. Potential, End ... Excitatory Postsynaptic Currents. Excitatory Postsynaptic Potential. Plate Potential, End. Plate Potentials, End. Postsynaptic ... Excitatory Postsynaptic Current Postsynaptic Current, Excitatory Postsynaptic Currents, Excitatory End Plate Potentials - ...
... electrode was placed at the stratum radiatum of the CA1 region for recording the excitatory postsynaptic field potentials ( ... Pre- and post-synaptic roles for DCC in memory consolidation in the adult mouse hippocampus. Mol Brain. 2020;13(1):56. ... Postsynaptic density protein 95 (PSD95) is crucial for synaptic plasticity and memory formation [62, 63]. This synaptic protein ... Moreover, the hippocampal LTP recorded from trained Prdx6−/− mice may be associated with accumulative levels of postsynaptic ...
... and kinetics of NMDA receptors act synergistically to stabilize synaptic integration of excitatory postsynaptic potentials ( ... Excitatory synaptic transmission in many neurons is mediated by two co-expressed ionotropic glutamate receptor subtypes, AMPA ... of somatic responses to spatiotemporal patterns of excitatory synaptic input presented at different initial membrane potentials ... resting membrane potential celsius=37 // nominal temperature of simulation Ri=100 // internal resistivity in ohm-cm Cm=1.0 // ...
Excitatory Postsynaptic Potentials. *Fear. *Female. *Generalization, Response. *HEK293 Cells. *Humans. *Interneurons. *LIM ...
Excitatory Postsynaptic Potentials. 1. 2018. 76. 0.670. Why? Glutamic Acid. 2. 2011 ...
Strength-frequency curve for micromagnetic neurostimulation through excitatory postsynaptic potentials (EPSPs) on rat ...
AAV, adeno-associated vector; AHP, afterhyperpolarization; fEPSP, field excitatory postsynaptic potential. Altogether, these ... Proc Natl Acad Sci U S A. Global genomic surveillance strategy for pathogens with pandemic and epidemic potential (Draft). ... This directly reduced synaptic glutamate concentration, hippocampal excitatory synaptic transmission in mice with normal or ... leading to impaired excitatory synaptic transmission and induction of LTP, which translated into a loss of contextual fear ...
... has been shown to have a divisive effect on subthreshold excitatory postsynaptic potential amplitudes. It has therefore been ... Shunting inhibition, a conductance increase with a reversal potential close to the resting potential of the cell, ... the spiking mechanism effectively clamps the somatic membrane potential to a value significantly above the resting potential, ... In addition, at distal synapses, shunting inhibition will also have an approximately subtractive effect if the excitatory ...
Furthermore, field excitatory postsynaptic potentials (fEPSCs) following postischemic LTP were assessed by electrophysiological ... of field excitatory postsynaptic potentials (fEPSPs) in the DG in vitro. The depression required the involvement of M1 ... The induction of postsynaptic LTP is dependent on the activation of postsynaptic NMDA receptors (NMDARs), while the presynaptic ... In the ACC, two major forms of long-term potentiation (LTP) coexist in excitatory synapses and lay the basis of chronic pain ...
Excitatory Postsynaptic Potentials Medicine & Life Sciences 88% * Neurons Medicine & Life Sciences 47% ... These results suggest that WGA augments hippocampal excitatory postsynaptic events via a postsynaptic mechanism. The results ... These results suggest that WGA augments hippocampal excitatory postsynaptic events via a postsynaptic mechanism. The results ... These results suggest that WGA augments hippocampal excitatory postsynaptic events via a postsynaptic mechanism. The results ...
... excitatory postsynaptic potentials) from neighbouring pyramids that exhibit paired pulse depression and display no ?sag? in ... horizontally oriented dendrites of CA2 interneurones express HCN subunits and postsynaptic receptors and receive excitatory ... Whether an individual neurone responds to a complex input pattern is determined by the strength of its excitatory inputs at ... manipulate Ih and postsynaptic receptors pharmacologically, reveal cellular markers and the localization of HCN subunits and ...
Excitatory neurotransmitters propagate a new action potential while inhibitory NTs inhibit the development of new action ... The neurotransmitter molecules bind with receptor proteins embedded in the membrane of the post synaptic neuron and activate a ... They work in the following way: an electric current (or action potential) travels down the length of a neuron, or nerve cell, ... Potential conditions include neurological problems, liver damage and bone abnormalities, although deficiency is far more common ...
Hiroshi Asanuma studied Motor cortex and Excitatory postsynaptic potential that intersect with Electrophysiology and ... Long-lasting potentiation of synaptic potentials in the motor cortex produced by stimulation of the sensory cortex in the cat: ...
... pyramid-pyramid excitatory postsynaptic potentials modified by presynaptic firing pattern and postsynaptic membrane potential ... Luo CH, Rudy Y. (1994). A dynamic model of the cardiac ventricular action potential. I. Simulations of ionic currents and ...
GCs were exposed to barrages of fast AMPAR-mediated excitatory postsynaptic currents (EPSCs), primarily relayed from the ... Action potentials in GCs were phase locked to network oscillations. Thus, theta-gamma-modulated synaptic currents may provide a ... GCs in vivo fired action potentials at low frequency, consistent with sparse coding in the dentate gyrus. ... EPSCs exhibited coherence with the field potential predominantly in the theta frequency band, whereas IPSCs showed coherence ...
FPI itself suppressed LTP and field excitatory post synaptic potentials (fEPSP) in the CA1 Schaffer collateral synapses; KA- ... FPI itself suppressed LTP and field excitatory post synaptic potentials (fEPSP) in the CA1 Schaffer collateral synapses; KA- ... FPI itself suppressed LTP and field excitatory post synaptic potentials (fEPSP) in the CA1 Schaffer collateral synapses; KA- ... FPI itself suppressed LTP and field excitatory post synaptic potentials (fEPSP) in the CA1 Schaffer collateral synapses; KA- ...
... although electrical stimulation generated monosynaptic excitatory postsynaptic potentials that were indistinguishable from ... although electrical stimulation generated monosynaptic excitatory postsynaptic potentials that were indistinguishable from ...
  • In general, you can think of the pyramidal neurons as the excitatory ones, and the stellates as the inhibitory ones. (
  • Depolarization of membrane potentials at the SYNAPTIC MEMBRANES of target neurons during neurotransmission. (
  • Excitatory synaptic transmission in many neurons is mediated by two co-expressed ionotropic glutamate receptor subtypes, AMPA and NMDA receptors, that differ in their kinetics, ion-selectivity, and voltage-sensitivity. (
  • The effect of the lectin wheat germ agglutinin (WGA), an inhibitor of ionotropic quisqualate receptor desensitization, on both evoked and spontaneous fast excitatory postsynaptic events was examined in cultured postnatal rat hippocampal neurons with the use of whole cell recordings. (
  • Here we report that the voltage-dependency and kinetics of NMDA receptors act synergistically to stabilize synaptic integration of excitatory postsynaptic potentials (EPSPs) across spatial and voltage domains. (
  • They receive fast EPSPs (excitatory postsynaptic potentials) from neighbouring pyramids that exhibit paired pulse depression and display no ?sag? (
  • Simultaneous paired recording were then used to calculate a correlation probability (CP) to infer the proportion of shared input based on the occurrence of simultaneous synaptic potentials. (
  • Shu Y, Hasenstaub A, Duque A, Yu Y, McCormick DA (2006) Modulation of intracortical synaptic potentials by presynaptic somatic membrane potential. (
  • When combined with AMPA conductance, the NMDA conductance balances voltage- and impedance-dependent changes in synaptic driving force, and distance-dependent attenuation of synaptic potentials arriving at the axon, to increase the fidelity of synaptic integration and EPSP-spike coupling across neuron state (i.e., initial membrane potential) and dendritic location of synaptic input. (
  • On the other side of the synapse, the neurotransmitter causes (via that sniffer mechanism) a small voltage change in the downstream neuron known as an excitatory postsynaptic potential (EPSP). (
  • WGA, at 580 nM, potentiated evoked fast excitatory postsynaptic currents (EPSCs) by increasing the amplitudes by 100 ± 27% (mean ± SE) and the time constant of decay from 5.8 ± 0.6 to 7.9 ± 0.5 ms. The increases in these parameters were not accompanied by changes in the current-voltage (I-V) relationship or pharmacological profile of the fast EPSCs. (
  • WGA did not alter the amplitude or time course of decay of inhibitory postsynaptic currents (IPSCs), and it did not alter neuronal input resistance or action potentials. (
  • GCs were exposed to barrages of fast AMPAR-mediated excitatory postsynaptic currents (EPSCs), primarily relayed from the entorhinal cortex, and inhibitory postsynaptic currents (IPSCs), presumably generated by local interneurons. (
  • In addition, at distal synapses, shunting inhibition will also have an approximately subtractive effect if the excitatory conductance is not small compared to the inhibitory conductance. (
  • Intracortical synaptic potential modulation by presynaptic somatic potential (Shu et al. (
  • 1993). Fluctuations in pyramid-pyramid excitatory postsynaptic potentials modified by presynaptic firing pattern and postsynaptic membrane potential using paired intracellular recordings in rat neocortex. (
  • Electrophysiological (ePhys) studies including paired-pulse stimulation for short-term presynaptic plasticity and long-term potentiation (LTP) of CA1 Schaffer collateral synapses of the hippocampus for postsynaptic function survey were followed at post-event 1 hour, 3 and 7 days respectively. (
  • Conclusion: Our data indicates that synaptic plasticity (i.e., both presynaptic and postsynaptic) suppression occurs in TBI followed by a seizure and that the interval between the TBI and seizure is an important factor in the severity of the resulting deficits. (
  • Polysynaptic excitatory postsynaptic potentials that trigger spasms after spinal cord injury in rats are inhibited by 5-HT1B and 5-HT1F receptors. (
  • AMPA receptors have fast kinetics and are voltage-insensitive, while NMDA receptors have slower kinetics and increased conductance at depolarized membrane potentials. (
  • We will therefore test the hypothesis that the long, horizontally oriented dendrites of CA2 interneurones express HCN subunits and postsynaptic receptors and receive excitatory inputs that are distinct from those of their vertically oriented dendrites in SR and SLM. (
  • We will employ dual and triple intracellular recordings to compare inputs to CA2 interneurones from pyramids in CA1, CA2 and CA3, manipulate Ih and postsynaptic receptors pharmacologically, reveal cellular markers and the localization of HCN subunits and postsynaptic receptors in these biocytin-labelled cells using confocal immuno-fluorescence and identify the locations of recorded synapses histologically. (
  • Simulations of synaptic integration in simplified and morphologically realistic dendritic trees revealed that the combined presence of AMPA and NMDA conductances reduces the variability of somatic responses to spatiotemporal patterns of excitatory synaptic input presented at different initial membrane potentials and/or in different dendritic domains. (
  • This moderating effect of the NMDA conductance on synaptic integration was robust across a wide range of AMPA-to-NMDA ratios, and results from synergistic interaction of NMDA kinetics (which reduces variability across membrane potential) and voltage-dependence (which favors stabilization across dendritic location). (
  • Averaged over several interspike intervals, the spiking mechanism effectively clamps the somatic membrane potential to a value significantly above the resting potential, so that the current through the shunting conductance is approximately independent of the firing rate. (
  • Insights Into the Role of the astroglial network that allows for better diffusion of glutamate released at synapses, leading to impaired excitatory synaptic transmission and induction of LTP, which translated into a loss of contextual fear memory pravachol cost. (
  • Shunting inhibition, a conductance increase with a reversal potential close to the resting potential of the cell, has been shown to have a divisive effect on subthreshold excitatory postsynaptic potential amplitudes. (
  • Selective activation of BK channels in small-headed dendritic spines suppresses excitatory postsynaptic potentials. (
  • Whether an individual neurone responds to a complex input pattern is determined by the strength of its excitatory inputs at that moment, its state at that time and importantly, by the inhibition it receives. (
  • This directly reduced synaptic glutamate concentration, hippocampal excitatory synaptic transmission in mice with normal or upregulated pravachol cost Cx30 expression. (
  • EPSCs exhibited coherence with the field potential predominantly in the theta frequency band, whereas IPSCs showed coherence primarily in the gamma range. (
  • Excitatory postsynaptic potentials can singly or in summation reach the trigger threshold for ACTION POTENTIALS. (
  • Properties of action potential initiation in neocortical pyramidal cells: evidence from whole cell axon recordings. (
  • Release of neurotransmitter happens when a brief electrical impulse (also known as a spike or action potential) is sent from the beginning of the axon near the cell body. (
  • These results suggest that WGA augments hippocampal excitatory postsynaptic events via a postsynaptic mechanism. (
  • The results further imply that ionotropic quisqualate receptor desensitization can modulate the amplitude and time course of decay of fast excitatory synaptic events. (
  • On T1 (acquisition trial), subjects were placed back in the human microbiome and aging remains sparse, some initial observations highlight the potential to pair mechanistic and translational microbiome research and the probability of sexual reproduction with endemic blast fungus through functional losses in a substitution at position 143 in the. (
  • GCs in vivo fired action potentials at low frequency, consistent with sparse coding in the dentate gyrus. (
  • Peripheral serotonin receptor 2B and transient receptor potential channel 4 mediate pruritus to serotonergic antidepressants in mice. (
  • We characterized the functional excitatory local input to these 3 cell subtypes in rat primary visual cortex using laser-scanning photostimulation. (
  • Hiroshi Asanuma studied Motor cortex and Excitatory postsynaptic potential that intersect with Electrophysiology and Stimulation. (
  • Muscle stretch failed to evoke detectable synaptic responses in 13 of 22 motoneurons, although electrical stimulation generated monosynaptic excitatory postsynaptic potentials that were indistinguishable from normal. (
  • In this study, an ultra-performance liquid chromatography-Q-Exactive hybrid quadrupole-Orbitrap mass spectrometry-based untargeted hippocampus high-throughput metabolomics method was first performed to screen for potential biomarkers in a schizophrenia-like state in a chronically administered ketamine-induced mouse model. (
  • A dynamic model of the cardiac ventricular action potential. (
  • One particular aspect of synaptic plasticity that has seldom been explored is the role of noncoding regions of the genome and the potential regulatory functions that they contain. (