neurons that relay information within the central nervous system are called
Central nervous system


nerve will carry both sensory and motor signals, but the nerves synapse at different regions of the spinal cord, either from the periphery to sensory relay neurons that relay the information to the CNS or from the CNS to motor neurons, which relay the information out. The spinal cord relays information up to the brain through spinal tracts through the "final common pathway" to the thalamus and ultimately to the cortex. Apart from the spinal cord, there are also peripheral nerves of the PNS that synapse through intermediaries or ganglia directly on
7478730
Dorsal root ganglion


A dorsal root ganglion (or spinal ganglion) (also known as a posterior root ganglion), is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the dorsal root ganglia. The axons of dorsal root ganglion neurons are known as afferents. In the peripheral nervous system, afferents refer to the axons that relay sensory information into the central nervous system (i.e. the brain and the spinal cord). These
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Interneuron


circuits with nearby neurons to analyze small pieces of information. Relay interneurons have long axons and connect circuits of neurons in one region of the brain with those in other regions. The interaction between interneurons allow the brain to perform complex functions such as learning, and decision-making. Unlike the peripheral nervous system (PNS), the central nervous system, including the brain, contains many interneurons. In the neocortex (making up about 80% of the human brain), approximately 20-30% of neurons are interneurons.
11848328
Interneuron


An interneuron (also called internuncial neuron, relay neuron, association neuron, connector neuron, intermediate neuron or local circuit neuron) is a broad class of neurons found in the human body. Interneurons create neural circuits, enabling communication between sensory or motor neurons and the central nervous system (CNS). They have been found to function in reflexes, neuronal oscillations, and neurogenesis in the adult mammalian brain. Interneurons can be further broken down into two groups: local interneurons and relay interneurons. Local interneurons have short axons and form
11848327
Gamma motor neuron


skeletofusimotor neurons. Gamma motor neurons are the efferent (sending signals away from the central nervous system) part of the fusimotor system, whereas muscle spindles are the afferent part, as they send signals relaying information from muscles toward the spinal cord and brain. Gamma bias is gamma motor neurons' consistent level of activity. Smaller neurons require a smaller amount of excitatory input to reach its threshold compared to larger neurons. Therefore, gamma motor neurons (smaller in size than alpha motor neurons) are more likely to fire than the larger
17181398
Motor neuron


and intercostal muscles), which are involved in locomotion. The three types of these neurons are the "alpha efferent neurons", "beta efferent neurons", and "gamma efferent neurons". They are called efferent to indicate the flow of information from the central nervous system (CNS) to the periphery. In addition to voluntary skeletal muscle contraction, alpha motor neurons also contribute to muscle tone, the continuous force generated by noncontracting muscle to oppose stretching. When a muscle is stretched, sensory neurons within the muscle spindle
19442890
Outline of the human nervous system


(PNS) – nervous system structures that do not lie within the CNS. A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Glial cells, commonly called neuroglia or glia, are supportive cells that maintain homeostasis, form myelin, and provide support and protection for the brain's neurons. A neuron (also known as a neurone or nerve cell) is an excitable cell in the
20967672
Vestibulospinal tract


The vestibulospinal tract is a neural tract in the central nervous system. Specifically, it is a component of the extrapyramidal system and is classified as a component of the medial pathway. Like other descending motor pathways, the vestibulospinal fibers of the tract relay information from nuclei to motor neurons. The vestibular nuclei receive information through the vestibulocochlear nerve about changes in the orientation of the head. The nuclei relay motor commands through the vestibulospinal tract. The function of these motor commands is to alter muscle tone, extend, and change the position
12995063
Sensory nerve


A sensory nerve, also called an afferent nerve, is a nerve that carries sensory information toward the central nervous system (CNS). It is a cable-like bundle of the afferent nerve fibers coming from sensory receptors in the peripheral nervous system (PNS). A motor nerve carries information from the CNS to the PNS, and both types of nerve are called peripheral nerves. Afferent nerve fibers link the sensory neurons throughout the body, in pathways to the relevant processing circuits in the central nervous system. Afferent nerve fibers
2287234
Segmentation in the human nervous system


and spinal cord, and the peripheral nervous system (PNS) comprising the nerve fibers that branch off from the spinal cord to all parts of the body. Both parts of the nervous system are actively involved in communicating signals between various parts of the body to ensure the smooth and efficient transfer of information that controls and coordinates the movement of muscles, and regulates organ functions. Neurons, which form the elemental unit of the nervous system, receive messages from their dendrites, relay the information as an electrical signal down the axon and
12814433
Glia


Glia, also called glial cells or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system. They maintain homeostasis, form myelin, and provide support and protection for neurons. In the central nervous system, glial cells include oligodendrocytes, astrocytes, ependymal cells, and microglia, and in the peripheral nervous system glial cells include Schwann cells and satellite cells. They have four main functions: (1) to surround neurons and hold them in place; (2
1733778
Baroreflex


the glossopharyngeal nerve (CN IX), the aortic arch baroreceptor axons travel within the vagus nerve (CN X). Baroreceptor activity travels along these nerves directly into the central nervous system to contact neurons within the nucleus of the solitary tract (NTS) in the brainstem. Baroreceptor information flows from these NTS neurons to both parasympathetic and sympathetic neurons within the brainstem. The NTS neurons send excitatory fibers (glutamatergic) to the caudal ventrolateral medulla (CVLM), activating the CVLM. The activated CVLM then sends inhibitory fibers (GABAergic
15815216
Somatic nervous system


The somatic nervous system (SNS or voluntary nervous system) is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles. The somatic nervous system consists of afferent nerves or sensory nerves, and efferent nerves or motor nerves. Afferent nerves are responsible for relaying sensation from the body to the central nervous system; efferent nerves are responsible for sending out commands from the CNS to the body, stimulating muscle contraction; they include all the non-sensory neurons connected with skeletal muscles and skin.
14032985
Baroreceptor


Baroreceptors (or archaically, pressoreceptors) are sensors located in the carotid sinus(at the bifurcation of external and internal carotids) and in the aortic arch. They sense the blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained. Baroreceptors are a type of mechanoreceptor sensory neuron that are excited by a stretch of the blood vessel. Thus, increases in the pressure of blood vessel triggers increased action potential generation rates and provides information to the central nervous system. This sensory information is used primarily
11103715
Gliotransmitter


because of the ability of glial cells to induce excitability with variations in Ca concentrations. Changes in the concentration of Ca correlate with currents from NMDA receptor-mediated neurons which are measured in neighboring neurons of the ventrobasal (VB) thalamus. Because glial cells greatly outnumber neurons in the brain, accounting for over 70% of all cells in the central nervous system, gliotransmitters released by astrocytes have the potential to be very influential and important within the central nervous system, as well as within other neural systems throughout the body. These
82326
Thought


neurons to other neurons within the brain and spinal cord. Neurons respond to stimuli, and communicate the presence of stimuli to the central nervous system, which processes that information and sends responses to other parts of the body for action. Neurons do not go through mitosis and usually cannot be replaced after being destroyed, although astrocytes have been observed to turn into neurons, as they are sometimes pluripotent. Psychologists have concentrated on thinking as an intellectual exertion aimed at finding an answer to a question or the solution of a practical problem
16439090
Sensory neuroscience


obtained from single cells. This is important since computations are performed within the dendrites of individual neurons. In most of the central nervous system, neurons communicate exclusively by sending each other action potentials, colloquially known as "spikes". It is therefore thought that all of the information a sensory neuron encodes about the outside world can be inferred by the pattern of its spikes. Current experimental techniques cannot measure individual spikes noninvasively. A typical single neuron experiment will consist of isolating a neuron (that is, navigating the neuron until
8509043
Sensory neuron


or "silent" nociceptors. Information coming from the sensory neurons in the head enters the central nervous system (CNS) through cranial nerves. Information from the sensory neurons below the head enters the spinal cord and passes towards the brain through the 31 spinal nerves. The sensory information traveling through the spinal cord follows well-defined pathways. The nervous system codes the differences among the sensations in terms of which cells are active. A sensory receptor's adequate stimulus is the stimulus modality for which it possesses the adequate sensory transduction apparatus
13931937
Signal transduction


cues, such as the presence of EGF, to intracellular events, such as the DNA damage resulting from replicative telomere attrition. Traditionally, signals that reach the central nervous system are classified as senses. These are transmitted from neuron to neuron in a process called synaptic transmission. Many other intercellular signal relay mechanisms exist in multicellular organisms, such as those that govern embryonic development. The majority of signal transduction pathways involve the binding of signaling molecules, known as ligands, to receptors that trigger events inside the cell. The binding of
9259668
Alpha motor neuron


Alpha (α) motor neurons (also called alpha motoneurons), are large, multipolar lower motor neurons of the brainstem and spinal cord. They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their contraction. Alpha motor neurons are distinct from gamma motor neurons, which innervate intrafusal muscle fibers of muscle spindles. While their cell bodies are found in the central nervous system (CNS), α motor neurons are also considered part of the somatic nervous system—a branch of the peripheral nervous system (PNS)—because
8482644
Olfactory bulb mitral cell


Mitral cells are neurons that are part of the olfactory system. They are located in the olfactory bulb in the mammalian central nervous system. They receive information from the axons of olfactory receptor neurons, forming synapses in neuropils called glomeruli. Axons of the mitral cells transfer information to a number of areas in the brain, including the piriform cortex, entorhinal cortex, and amygdala. Mitral cells receive excitatory input from olfactory sensory neurons and external tufted cells on their primary dendrites, whereas inhibitory input arises either from granule cells onto their lateral
14073692
Neuroanatomy


wrap around and segregate them into nerve fascicles. The vertebrate nervous system is divided into the central and peripheral nervous systems. The central nervous system (CNS) consists of the brain, retina, and spinal cord, while the peripheral nervous system (PNS) is made up of all the nerves outside of the CNS that connect it to the rest of the body. The PNS is further subdivided into the somatic and autonomic nervous systems. The somatic nervous system is made up of "afferent" neurons, which bring sensory information
19875770
Neuroscience


another. Many neurons extrude a long thin filament of axoplasm called an axon, which may extend to distant parts of the body and are capable of rapidly carrying electrical signals, influencing the activity of other neurons, muscles, or glands at their termination points. A nervous "system" emerges from the assemblage of neurons that are connected to each other. The vertebrate nervous system can be split into two parts: the central nervous system (defined as the brain and spinal cord), and the peripheral nervous system. In many
1439075
Odor


signal reaches a threshold, the neuron fires, which sends a signal traveling along the axon to the olfactory bulb, a part of the limbic system of the brain. Interpretation of the smell begins there, relating the smell to past experiences and in relation to the substance(s) inhaled. The olfactory bulb acts as a relay station connecting the nose to the olfactory cortex in the brain. Olfactory information is further processed and forwarded to the central nervous system (CNS), which controls emotions and behavior as well as basic thought processes
6521800
Chemical synapse


Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous system. They are crucial to the biological computations that underlie perception and thought. They allow the nervous system to connect to and control other systems of the body. At a chemical synapse, one neuron releases neurotransmitter molecules into a small space (the synaptic cleft) that is adjacent to another neuron. The neurotransmitters
8174438
Nerve


A nerve is an enclosed, cable-like bundle of nerve fibres called axons, in the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of the axons to peripheral organs or, in the case of sensory nerves, from the periphery back to the central nervous system. Each axon within the nerve is an extension of an individual neuron, along with other supportive cells such as Schwann cells that coat the axons in myelin. Within a nerve, each
1710559
Nonsynaptic plasticity


long-term potentiation, however these concepts are generally considered types of synaptic plasticity. Central nervous system (CNS) neurons integrate signals from many neurons. In the short term, it is important to have changes in activity of the neuron because this is how information is conveyed in the nervous system (Hebbian plasticity). However, for long-term sustainability, drift towards excitability or inexcitability will disturb the circuit's ability to convey information (homeostatic plasticity). Long-term potentiation (LTP) induces a higher firing rate
11110356
Parasympathetic nervous system


nervous system, efferent parasympathetic nerve signals are carried from the central nervous system to their targets by a system of two neurons. The first neuron in this pathway is referred to as the preganglionic or presynaptic neuron. Its cell body sits in the central nervous system and its axon usually extends to synapse with the dendrites of a postganglionic neuron somewhere else in the body. The axons of presynaptic parasympathetic neurons are usually long, extending from the CNS into a ganglion that is either very close to or embedded in their target organ. As
18349922
Sensory neuron


Sensory neurons also known as afferent neurons are neurons that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord (which is part of the Central Nervous System). This sensory information travels along afferent nerve fibers in an afferent or sensory nerve, to the brain via the spinal cord. The stimulus can come from "extoreceptors" outside the body, for example
13931927
Lateral grey column


column. The nervous system is the system of neurons, or nerve cells, that relay electrical signals through the brain and body. A nerve cell receives signals from other nerve cells through tree-branch-like extensions called dendrites and passes signals on through a long extension called an axon (or nerve fiber). Synapses are places where one cell's axon passes information to another cell's dendrite by sending chemicals called neurotransmitters across a small gap called a synaptic cleft. Synapses occur in various locations, including ganglia (singular:
14647400
Olfactory ensheathing glia


that express LYZ are thought to play an important role in immunoprotection in the mucosa, where neurons are directly exposed to the external environment. OEG have been tested successfully in experimental axonal regeneration in adult rats with traumatic spinal cord damage, and clinical trials are currently being conducted to obtain more information on spinal cord injuries and other neurodegenerative diseases. In the peripheral nervous system OEG are dispersed within the olfactory epithelium and the olfactory nerve. In the central nervous system, OEG are found within the outer two layers of the olfactory bulb.
4499642
Olfactory ensheathing glia


ability is associated with olfactory ensheathing glia. New olfactory receptor neurons must project their axons through the central nervous system to an olfactory bulb in order to be functional. The growth and regeneration of olfactory axons can be attributable to OEG, as they form the fascicles through which axons grow from the peripheral nervous system into the central nervous system. Olfactory receptor neurons have an average lifespan of 6–8 weeks and therefore must be replaced by cells differentiated from the stem cells that are within a layer at the nearby epithelium's base. Axonal growth
4499646
Nerve guidance conduit


Glial cells are necessary for supporting the growth and maintenance of neurons in the peripheral and central nervous system. Most glial cells are specific to either the peripheral or central nervous system. Schwann cells are located in the peripheral nervous system where they myelinate the axons of neurons. Astrocytes are specific to the central nervous system; they provide nutrients, physical support, and insulation for neurons. They also form the blood brain barrier. Olfactory ensheathing cells, however, cross the CNS-PNS boundary, because they guide olfactory receptor neurons from
15622029
Neuron


, along with the glial cells that give them structural and metabolic support. The nervous system is made up of the central nervous system, which includes the brain and spinal cord, and the peripheral nervous system, which includes the autonomic and somatic nervous systems. In vertebrates, the majority of neurons belong to the central nervous system, but some reside in peripheral ganglia, and many sensory neurons are situated in sensory organs such as the retina and cochlea. Axons may bundle into fascicles that make up the nerves in the peripheral nervous
1233154
Neuroimmune system


and has been found to upregulate inflammatory mediating molecules. Glial cells can effectively recognize pathogens in both the central nervous system and in peripheral tissues. When glial cells recognize foreign pathogens through the use of cytokine and chemokine signaling, they are able to relay this information to the CNS. The result is an increase in depressive symptoms. Chronic activation of glial cells however leads to neurodegeneration and neuroinflammation. Microglial cells are of the most prominent types of glial cells in the brain. One of their main functions is phagocytozing cellular debris following neuronal
11834258
Neurotoxin


that while BTX inhibits muscular contractions, TeNT induces them. Though both toxins inhibit vesicle release at neuron synapses, the reason for this different manifestation is that BTX functions mainly in the peripheral nervous system (PNS) while TeNT is largely active in the central nervous system (CNS). This is a result of TeNT migration through motor neurons to the inhibitory neurons of the spinal cord after entering through endocytosis. This results in a loss of function in inhibitory neurons within the CNS resulting in systemic muscular contractions. Similar to the prognosis
16423596
Nerve supply to the skin


. Protopathic neurons are responsible for detecting pain, itch, tickle, and temperature. The different types of stimuli that are detected by a given receptor allow for a relative specificity between stimuli and receptor. The sensory modality that is detected by the afferent fibers is an important factor to consider because it determines the pathway that the dorsal root ganglion neurons will take within the central nervous system. The sensory neurons coming from the body synapse in the dorsal horn of the spinal cord, bringing in information about touch sensations (epicritic),
9648882
Non-spiking neuron


Non-spiking neurons are neurons that are located in the central and peripheral nervous systems and function as intermediary relays for sensory-motor neurons. They do not exhibit the characteristic spiking behavior of action potential generating neurons. Non-spiking neural networks are integrated with spiking neural networks to have a synergistic effect in being able to stimulate some sensory or motor response while also being able to modulate the response. There are an abundance of neurons that propagate signals via action potentials and the mechanics of this particular kind of transmission is well understood
16908282
Acetylcholine


are both organized in essentially the same way: preganglionic neurons in the central nervous system send projections to neurons located in autonomic ganglia, which send output projections to virtually every tissue of the body. In both branches the internal connections, the projections from the central nervous system to the autonomic ganglia, use acetylcholine as a neurotransmitter to innervate (or excite) cholinergic neurons (neurons expressing nicotinic acetylcholine receptors). In the parasympathetic nervous system the output connections, the projections from ganglion neurons to tissues that don't belong to the nervous
7706603
Myenteric plexus


parasympathetic and sympathetic fibers that connect either the central and enteric nervous systems or connect the central nervous system directly with the digestive tract. Through these cross connections, the gut can provide sensory information to the CNS, and the CNS can affect gastrointestinal function. Connection to the central nervous system also means that signals from outside of the digestive system can be relayed to the digestive system: for instance, the sight of appealing food stimulates secretion in the stomach. The enteric nervous system makes use of over 30 different neurotransmitters, most similar
18771629
Neuron


system (like strands of wire make up cables). Bundles of axons in the central nervous system are called tracts. Neurons are highly specialized for the processing and transmission of cellular signals. Given their diversity of functions performed in different parts of the nervous system, there is a wide variety in their shape, size, and electrochemical properties. For instance, the soma of a neuron can vary from 4 to 100 micrometers in diameter. The accepted view of the neuron attributes dedicated functions to its various anatomical components; however,
1233155
Andrea Brand


after damage to the brain or spinal cord. Before we can understand how to repair the nervous system, however, we must first learn how the nervous system is put together. Of all the tissues and organs in the human body the nervous system is the most intricate and complex, consisting of more than one trillion neurons. These neurons make precise connections with each other to form functional networks that can transmit information at amazing speed over considerable distances. “Neurons are produced by multipotent precursors called stem cells. Neural stem cells divide
10303227
Neuroregeneration


the environment. It is important to note that central nervous system axons have been proven to regrow in permissive environments; therefore, the primary problem to central nervous system axonal regeneration is crossing or eliminating the inhibitory lesion site. Another problem is that the morphology and functional properties of central nervous system neurons are highly complex, for this reason a neuron functionally identical cannot be replaced by one of another type (Llinás' law). Glial cell scar formation is induced following damage to the nervous system. In the central nervous system
20921054
Ligand-gated ion channel


. Ligands: GABA receptors are major inhibitory neurotransmitter expressed in the major interneurons in animal cortex. GABA receptors are ligand-gated ion channels. GABA ("gamma"-aminobutyric acid), the endogenous ligand for these receptors, is the major inhibitory neurotransmitter in the central nervous system. When activated, it mediates Cl flow into the neuron, hyperpolarizing the neuron. GABA receptors occur in all organisms that have a nervous system. Due to their wide distribution within the nervous system of mammals, they play a role in virtually all brain functions
16238867
Purinergic receptor


channels indicates the presence of only two transmembrane domains within the channels. These receptors are greatly distributed in neurons and glial cells throughout the central and peripheral nervous systems. P2X receptors mediate a large variety of responses including fast transmission at central synapses, contraction of smooth muscle cells, platelet aggregation, macrophage activation, and apoptosis. Moreover, these receptors have been implicated in integrating functional activity between neurons, glial, and vascular cells in the central nervous system, thereby mediating the effects of neural activity during development, neurodegeneration, inflammation,
709934
Astrocyte


are macroglial cells in the central nervous system. Astrocytes are derived from heterogeneous populations of progenitor cells in the neuroepithelium of the developing central nervous system. There is remarkable similarity between the well known genetic mechanisms that specify the lineage of diverse neuron subtypes and that of macroglial cells. Just as with neuronal cell specification, canonical signaling factors like Sonic hedgehog (SHH), Fibroblast growth factor (FGFs), WNTs and bone morphogenetic proteins (BMPs), provide positional information to developing macroglial cells through morphogen gradients along the dorsal–ventral
17141787
Somatic nervous system


somatic nervous system consists of two parts: The somatic nervous system controls all voluntary muscular systems within the body, and the process of voluntary reflex arcs. The basic route of nerve signals within the efferent somatic nervous system involves a sequence that begins in the upper cell bodies of motor neurons (upper motor neurons) within the precentral gyrus (which approximates the primary motor cortex). Stimuli from the precentral gyrus are transmitted from upper motor neurons and down the corticospinal tract, via axons to control skeletal (voluntary) muscles. These
14032987
Central nervous system disease


the peripheral nervous system. It also conducts motor information to the body's skeletal muscles, cardiac muscles, smooth muscles, and glands. There are 31 pairs of spinal nerves along the spinal cord, all of which consist of both sensory and motor neurons. The spinal cord is protected by vertebrae and connects the peripheral nervous system to the brain, and it acts as a "minor" coordinating center. The brain serves as the organic basis of cognition and exerts centralized control over the other organs of the body. The brain
15979615
Astrocyte


to neurons through Ca-dependent release of glutamate. Such discoveries have made astrocytes an important area of research within the field of neuroscience. Astrocytes are a sub-type of glial cells in the central nervous system. They are also known as "astrocytic glial cells." Star-shaped, their many processes envelop synapses made by neurons. Astrocytes are classically identified using histological analysis; many of these cells express the intermediate filament glial fibrillary acidic protein (GFAP). Several forms of astrocytes exist in the central nervous system including
17141784
Classification of peripheral nerves


The classification of peripheral nerves in the peripheral nervous system (PNS) groups the nerves into two main groups, the somatic and the autonomic nervous systems. Together, these two systems provide information regarding the location and status of the limbs, organs, and the remainder of the body to the central nervous system (CNS) via nerves and ganglia present outside of the spinal cord and brain. The somatic nervous system directs all voluntary movements of the skeletal muscles, and can be sub-divided into afferent and efferent neuronal flow.
12025874
Traumatic brain injury modeling


are removed. Many experiments have been conducted in attempts to create a general model for the mechanical tolerance of neurons within the Central Nervous System (CNS). One such "in vitro" model has found that CNS neurons have a lower threshold for stress and strain loads than Peripheral Nervous System (PNS) neurons. "in vivo" models are the opposite end of the spectrum. In these models, specialization is sacrificed in order to observe brain reactions in the context of the whole body. While this gives a better understanding
12542881
Reflex bradycardia


sinus sense this increase in blood pressure and relay the information to the cardiovascular centres in the medulla oblongata. In order to maintain homeostasis, the cardiovascular centres activate the parasympathetic nervous system. Via the vagus nerve, the parasympathetic nervous system stimulates neurons that release the neurotransmitter acetylcholine (ACh) at synapses with cardiac muscle cells. Acetylcholine then binds to M muscarinic receptors, causing the decrease in heart rate that is referred to as reflex bradycardia. The M muscarinic receptors decrease the heart rate by inhibiting depolarization of the sinoatrial node via G
13218761
Neuronal encoding of sound


neurons ideal for electromechanical feedback. Type II neurons can be physiologically manipulated to innervate inner hair cells provided outer hair cells have been destroyed either through mechanical damage or by chemical damage induced by drugs such as gentamicin. The auditory nervous system includes many stages of information processing between the ear and cortex. Primary auditory neurons carry action potentials from the cochlea into the transmission pathway shown in the adjacent image. Multiple relay stations act as integration and processing centers. The signals reach the first level of cortical processing at the primary auditory cortex (
10851437
Nervous system disease


is split up into 4 lobes: the temporal, parietal the occipetal, and the frontal The brain has over 100 billion neurons and it uses about 20% of the body's oxygen. The spinal cord runs through most of the back. The spinal cord contains a total of 31 spinal nerves in between each vertebrae. The nerves connect to the peripheral nervous system. The peripheral nervous system connects to the muscles and glands and sends information to the central nervous system. There are a number of different tests that can be used
20169969
Pallesthesia


that it can be used to identify disorders within the neural pathways. Because there are few areas in the neural pathway where the sensation and perception of vibration can be disturbed, this testing enables doctors to more accurately diagnose their patients' health. It can help to identify effects of other diseases on the nervous system, such as diabetes mellitus. The peripheral nervous system is composed of afferent and efferent neurons; disorder of these neurons is called peripheral neuropathy. Vibration examination can detect and localize disorders of the peripheral nervous system. A
16774004
Muscle spindle


Muscle spindles are stretch receptors within the body of a muscle that primarily detect changes in the length of the muscle. They convey length information to the central nervous system via afferent nerve fibers. This information can be processed by the brain as proprioception. The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, for example, by activating motor neurons via the stretch reflex to resist muscle stretch. The muscle spindle has both sensory and motor components. Muscle spindles are found within the
7296247
Peripherin


axons of neurons in the peripheral nervous system. These include small-sized root ganglion neurons, lower motor neurons, sensory and motor neurons of the cranial nerves, and autonomic neurons in ganglia and the enteric nervous system. It is also expressed in the central nervous system in a small set of brainstem and spinal cord neurons that have projections toward peripheral structures. Some of these structures include the hypothalamic magnocellular nuclei, pontine cholinergic nuclei, some cerebellar nuclei, and scattered neurons in the cerebral cortex. They can also be found in
10734121
Central nervous system cavernous hemangioma


Central nervous system cavernous hemangioma is a cavernous hemangioma that arises in the central nervous system (CNS). It can be considered to be a variant of hemangioma, and is characterized by grossly large dilated blood vessels and large vascular channels, less well circumscribed, and more involved with deep structures, with a single layer of endothelium and an absence of neuronal tissue within the lesions. These thinly walled vessels resemble sinusoidal cavities filled with stagnant blood. Blood vessels in patients with cerebral cavernous malformations (CCM) can range from a few
5425359
Visual system


on each side of the brain, carry information from the thalamic lateral geniculate nucleus to layer 4 of the visual cortex. The P layer neurons of the LGN relay to V1 layer 4C β. The M layer neurons relay to V1 layer 4C α. The K layer neurons in the LGN relay to large neurons called blobs in layers 2 and 3 of V1. There is a direct correspondence from an angular position in the visual field of the eye, all the way through the optic tract to a nerve position in V1 (
9659671
Central nervous system primitive neuroectodermal tumor


A central nervous system primitive neuroectodermal tumor, often abbreviated as PNET, supratentorial PNET, or CNS-PNET, is one of the 3 types of embryonal central nervous system tumors defined by the World Health Organization (medulloblastoma, atypical teratoid rhabdoid tumor, and PNET). It is considered an embryonal tumor because it arises from cells partially differentiated or still undifferentiated from birth. Those cells are usually neuroepithelial cells, stem cells destined to turn into glia or neurons. It can occur anywhere within the spinal cord and cerebrum and can have
4165480
Grey column


spinal cord. It receives afferent input from muscle fibers and joints. The lateral grey column, or the lateral horn of spinal cord, is part of the sympathetic nervous system and receives input from brain stem, organs, and hypothalamus. The lateral column is only present in the thoracic region and upper lumbar segments. The lateral grey column contains neurons supplying nerves to the muscles of the limbs, preganglionic cell bodies of the autonomic nervous system and sensory relay neurons. Neurons in the anterior column have been shown to be affected by
11942062
Gliotransmitter


called Müller cells, and retinal neurons. The word “glia” illustrates the original belief among scientists that these cells play a passive role in neural signaling, being responsible only for neuronal structure and support within the brain. Glial cells cannot produce action potentials and therefore were not suspected as playing an important and active communicative role in the central nervous system, because synaptic transmission between neurons is initiated with an action potential. However, research shows that these cells express excitability with changes in the intracellular concentrations of Ca. Gliotransmission occurs
82325
Human body


sensory information, thought, memory, cognition and other such functions. It remains a matter of some debate whether the CNS directly gives rise to consciousness. The peripheral nervous system (PNS) is mostly responsible for gathering information with sensory neurons and directing body movements with motor neurons. From a functional perspective, the nervous system is again typically divided into two component parts: the somatic nervous system (SNS) and the autonomic nervous system (ANS). The SNS is involved in voluntary functions like speaking and sensory processes. The
9395827
Nervous system


do not lie within the CNS. The large majority of the axon bundles called nerves are considered to belong to the PNS, even when the cell bodies of the neurons to which they belong reside within the brain or spinal cord. The PNS is divided into somatic and visceral parts. The somatic part consists of the nerves that innervate the skin, joints, and muscles. The cell bodies of somatic sensory neurons lie in dorsal root ganglia of the spinal cord. The visceral part, also known as the autonomic nervous system,
2090371
Ganglion


form a complex system of ganglia known as a plexus. Ganglia provide relay points and intermediary connections between different neurological structures in the body, such as the peripheral and central nervous systems. Among vertebrates there are three major groups of ganglia: In the autonomic nervous system, fibers from the central nervous system to the ganglia are known as preganglionic fibers, while those from the ganglia to the effector organ are called postganglionic fibers. The term "ganglion" refers to the peripheral nervous system. However, in the brain (part of
11876196
Trisynaptic circuit


Information from the DG is directed to the pyramidal cells of CA3 through mossy fibres. Neurons within the DG are famous for being one of two nervous system areas capable of neurogenesis, the growth or development of nervous tissue. The CA3 is a portion of the hippocampal formation adjacent to the dentate gyrus. Input is received from the granule cells of the dentate gyrus through the mossy fibres. The CA3 is rich in pyramidal neurons (like those found throughout the neocortex), which project mainly to the CA1 pyramidal neurons via the Schaffer
13453890
Enteric nervous system


at some hospitals. The enteric nervous system has been described as a "second brain" for several reasons. The enteric nervous system can operate autonomously. It normally communicates with the central nervous system (CNS) through the parasympathetic (e.g., via the vagus nerve) and sympathetic (e.g., via the prevertebral ganglia) nervous systems. However, vertebrate studies show that when the vagus nerve is severed, the enteric nervous system continues to function. In vertebrates, the enteric nervous system includes efferent neurons, afferent neurons, and
18349988
Physiological psychology


of the nerve cells also called neurons. Through the system, messages are transmitted to body tissues such as a muscle. There are two major subdivisions in the nervous system known as the central and peripheral nervous system. The central nervous system is composed of the brain and spinal cord. The brain is the control center of the body and contains millions of neural connections. This organ is responsible for sending and receiving messages from the body and its environment. Each part of the brain is specialized for different aspects of the human being
15764765
Marcello Costa


discoveries about the role of neurons in driving the activity of the gut, and in recognising that a person's neurological system shapes their thoughts, culture, intellectual capacity, emotions and our bodily functions". Costa's application of a systematic approach to new methods has made the neuronal structure of the enteric nervous system one of the best understood parts of the nervous system in mammals. Observations in this system have also guided understanding the function of neurons in the central nervous system. The studies he conducted into neuronal reflexes that enable intestinal
2396398
Sandhoff disease


on the 14 exons in the HEX B gene located within chromosome 5 (see figure bottom), leading to the differences in severities of the symptoms. The difference in the codons has the consequence of inhibiting two enzymes located in the lysosomes of the neurons of the central nervous system. Lysosomes contain various enzymes to break down byproducts and toxins to ensure they do not accumulate enough to interfere with the function of the central nervous system. Using restriction enzymes, it was discovered that a mutation on chromosome 5 particularly within the C1214T
1527555
Nervous tissue


Nervous tissue, also called neural tissue or nerve tissue, is the main tissue component of the nervous system. The nervous system regulates and controls bodily functions and activity and consists of two parts: the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the branching peripheral nerves. It is composed of neurons, or nerve cells, which receive and transmit impulses, and neuroglia, also known as glial cells or glia, which assist the propagation of the nerve impulse
20420951
Neuron


dendrites and axons often act in ways contrary to their so-called main function. Axons and dendrites in the central nervous system are typically only about one micrometer thick, while some in the peripheral nervous system are much thicker. The soma is usually about 10–25 micrometers in diameter and often is not much larger than the cell nucleus it contains. The longest axon of a human motor neuron can be over a meter long, reaching from the base of the spine to the toes. Sensory neurons can have axons that run from the
1233156
Functional electrical stimulation


FET or FEST). In other words, the FEST is used as a short-term intervention to help the central nervous system of the person to re-learn how to execute impaired functions, instead of making the person dependent on neuroprostheses for the rest of her or his life. Neurons are electrically active cells. In neurons, information is coded and transmitted as a series of electrical impulses called action potentials, which represent a brief change in cell electric potential of approximately 80–90 mV. Nerve signals are frequency modulated; i.e. the
10970021
Species-typical behavior


an attack from another creature), the genes that coded for those brain circuits are more likely to be passed on. A heavily studied example of a fixed action pattern is the feeding behavior of the Helisoma trivolvis (pulmonata), a type of snail. A study has shown that the intricate connections within the buccal ganglia (see nervous system of gastropods) form a central system whereby sensory information stimulates feeding in the helisoma. More specifically, a unique system of communication between three classes of neurons in the buccal ganglia are responsible
10272150
Cholecystokinin


activate the CCK-A receptor, but their biological role remains unclear. CCK plays important physiological roles both as a neuropeptide in the central nervous system and as a peptide hormone in the gut. It participates in a number of processes such as digestion, satiety and anxiety. CCK is synthesized and released by enteroendocrine cells in the mucosal lining of the small intestine (mostly in the duodenum and jejunum), called I cells, neurons of the enteric nervous system, and neurons in the brain. It is released rapidly into the
4478197
Autonomic nervous system


as pain from the dermatome corresponding to the spinal segment. Motor neurons of the autonomic nervous system are found in ‘’autonomic ganglia’’. Those of the parasympathetic branch are located close to the target organ whilst the ganglia of the sympathetic branch are located close to the spinal cord. The sympathetic ganglia here, are found in two chains: the pre-vertebral and pre-aortic chains. The activity of autonomic ganglionic neurons is modulated by “preganglionic neurons” located in the central nervous system. Preganglionic sympathetic neurons are
4637114
Nervous system


isolated cells. In bilaterian animals, which make up the great majority of existing species, the nervous system has a common structure that originated early in the Ediacaran period, over 550 million years ago. The nervous system contains two main categories or types of cells: neurons and glial cells. The nervous system is defined by the presence of a special type of cell—the neuron (sometimes called "neurone" or "nerve cell"). Neurons can be distinguished from other cells in a number of ways, but their
2090365
Neuron doctrine


a central tenet of modern neuroscience, recent studies suggest that there are notable exceptions and important additions to our knowledge about how neurons function. Electrical synapses are more common in the central nervous system than previously thought. Thus, rather than functioning as individual units, in some parts of the brain large ensembles of neurons may be active simultaneously to process neural information. Electrical synapses are formed by gap junctions that allow molecules to directly pass between neurons, creating a cytoplasm-to-cytoplasm connection. Furthermore, the phenomenon of cotransmission,
6282209
Pallesthesia


are carried by the fasciculus gracilis into the medulla. If the neurons are coming from the upper limbs; they are carried by the fasciculus cuneatus. In the medulla, at the dorsal column, nuclei of the first-order neuron synapse with the second-order neuron, which then decussates (crosses over to the other side of the central nervous system) into the medial lemniscus. The second-order neuron then carries the information to the ventral posterolateral nucleus of the thalamus and then the somatosensory cortex in the parietal lobe.
16773999
Development of the nervous system in humans


is the movement of Cajal-Retzius cells within the marginal zone of the cortical neuroepithelium. There is also a method of neuronal migration called multipolar migration. This is seen in multipolar cells, which are abundantly present in the cortical intermediate zone. They do not resemble the cells migrating by locomotion or somal translocation. Instead these multipolar cells express neuronal markers and extend multiple thin processes in various directions independently of the radial glial fibers. Neurotrophic factors are molecules which promote and regulate neuronal survival in the developing nervous system. They are distinguished
2217907
Neuroanatomy


text Cerebri anatome which is considered the foundation of neuroanatomy. The subsequent three hundred and fifty some years has produced a great deal of documentation and study of the neural systems. At the tissue level, the nervous system is composed of neurons, glial cells, and extracellular matrix. Both neurons and glial cells come in many types (see, for example, the nervous system section of the list of distinct cell types in the adult human body). Neurons are the information-processing cells of the nervous system: they sense
19875767
Cultured neuronal network


A cultured neuronal network is a cell culture of neurons that is used as a model to study the central nervous system, especially the brain. Often, cultured neuronal networks are connected to an input/output device such as a multi-electrode array (MEA), thus allowing two-way communication between the researcher and the network. This model has proved to be an invaluable tool to scientists studying the underlying principles behind neuronal learning, memory, plasticity, connectivity, and information processing. Cultured neurons are often connected via computer
8590537
Anatomy


stimulus. In more complex animals, specialized receptor cells such as chemoreceptors and photoreceptors are found in groups and send messages along neural networks to other parts of the organism. Neurons can be connected together in ganglia. In higher animals, specialized receptors are the basis of sense organs and there is a central nervous system (brain and spinal cord) and a peripheral nervous system. The latter consists of sensory nerves that transmit information from sense organs and motor nerves that influence target organs. The peripheral nervous system is divided into the somatic
71934
Efferent nerve fiber


Efferent nerve fibers refer to axonal projections that exit a particular region; as opposed to afferent projections that arrive at the region. These terms have a slightly different meaning in the context of the peripheral nervous system (PNS) and central nervous system (CNS). The efferent fiber is a long process projecting far from the neuron's body that carries nerve impulses away from the central nervous system toward the peripheral effector organs (mainly muscles and glands). A bundle of these fibers is called a motor nerve or an efferent nerve
11941971
Feature detection (nervous system)


and narrow tuning. The separate processing of information continues passed the primary sensory neurons into the electrosensory lateral-line lobe (ELL) where spherical cells relay phase or time information to higher centers and pyramidal cells code for amplitude information. As a result, we also consider the class of spherical and pyramidal cells located in the ELL to be feature detectors. More specifically, pyramidal cells are considered feature detectors that respond to the amplitude of the stimulus. One class of pyramidal cell, E-cells, respond to increases; a
17641647
Myelinogenesis


Myelinogenesis is generally the proliferation of myelin sheaths in the nervous system, and specifically the progressive myelination of nerve axon fibers in the central nervous system. This is a non-simultaneous process that occurs primarily postnatally in mammalian species, beginning in the embryo during the midst of early development and finishing after birth. The myelination process allows neuronal signals to propagate down an axon more swiftly without the loss of signal. This enables better connectivity within specific brain regions and also improves broader neuronal pathways connecting spatially separate regions required for many sensory,
13177784
Psalmotoxin


when the H-concentration in the environment of the neuron is slightly higher compared to resting H-concentrations (pH = 7.4). The expression of ASIC1a is high in both the central nervous system and in the sensory neurons of the dorsal root ganglia. ASIC1b is only expressed in sensory neurons. Expression of ASIC1a in the central nervous system relates to the involvement of ASIC1a in higher brain functions, such as learning, memory and fear conditioning. Expression of ASIC1a and ASIC1b in sensory neurons relates to their involvement in nociception and
19266304
Nobel Prize controversies


twins united by the shoulders, scientific adversaries of such contrasting character!". The neuron doctrine turned out to be a more correct description, and Golgi was proved wrong with the development of electron microscopy in the 1950s by which it was clearly demonstrated that neurons are individual cells in the nervous system, and that they are interconnected through gaps called synapses. Recent studies suggest that there are notable exceptions. Electrical synapses are more common in the central nervous system than previously thought. Thus, rather than functioning as individual units, in
13000277
Phase resetting in neurons


Phase resetting in neurons is a behavior observed in different biological oscillators and plays a role in creating neural synchronization as well as different processes within the body. Phase resetting in neurons is when the dynamical behavior of an oscillation is shifted. This occurs when a stimulus perturbs the phase within an oscillatory cycle and a change in period occurs. The periods of these oscillations can vary depending on the biological system, with examples such as: (1) neural responses can change within a millisecond to quickly relay information; (2) In
12542775
Baroreceptor


synapses) transmit this information to neurons within the solitary nucleus which lies in the medulla. Reflex responses from such baroreceptor activity can trigger increases or decreases in the heart rate. Arterial baroreceptor sensory endings are simple, splayed nerve endings that lie in the tunica adventitia of the artery. An increase in the mean arterial pressure increases depolarization of these sensory endings, which results in action potentials. These action potentials are conducted to the solitary nucleus in the central nervous system by axons and have a reflex effect on the cardiovascular system through autonomic
11103718
Ultrasound avoidance


understandable since crickets don't only need to listen to bats, but also to each other. Crickets have broad frequency sensitivity to different types of echolocating calls. One specific auditory interneuron, the AN2 interneuron, exhibits remarkably rapid responses to echolocating call stimuli. All these receptors synapse on a far lower number of interneurons that relay the receptors' information to the cricket's central nervous system. In the "Teleogryllus" cricket, two ascending interneurons carry information to the brain- one carries information about cricket song (around 5 kHz) while
3646357
Stimulus (physiology)


and the motor neuron to which it is connected. The spot at which the motor neuron attaches to the muscle fiber is known as the neuromuscular junction. When muscles receive information from internal or external stimuli, muscle fibers are stimulated by their respective motor neuron. Impulses are passed from the central nervous system down neurons until they reach the motor neuron, which releases the neurotransmitter acetylcholine (ACh) into the neuromuscular junction. ACh binds to nicotinic acetylcholine receptors on the surface of the muscle cell and opens ion channels, allowing sodium ions
12054047
Lymnaea stagnalis


a total of ~20,000 neurons, many of them individually identifiable, organized in a ring of interconnected ganglia. Most neurons of the "Lymnaea stagnalis" central nervous system are large in size (diameter: up to ~100 μm), thus allowing electrophysiological dissection of neuronal networks that has yielded profound insights in the working mechanisms of neuronal networks controlling relatively simple behaviors such as feeding, respiration, locomotion, and reproduction. Studies using the central nervous system of "Lymnaea stagnalis" as a model organism have also identified novel cellular and molecular
7862081
Gastrointestinal physiology


in the bile. The digestive system has a complex system of motility and secretion regulation which is vital for proper function. This task is accomplished via a system of long reflexes from the central nervous system (CNS), short reflexes from the enteric nervous system (ENS) and reflexes from GI peptides working in harmony with each other. Long reflexes to the digestive system involve a sensory neuron sending information to the brain, which integrates the signal and then sends messages to the digestive system. While in some situations, the sensory
6352755
Motor system


The motor system is the set of central and peripheral structures in the nervous system that support motor functions, i.e. movement. Peripheral structures may include skeletal muscles and neural connections with muscle tissues. Central structures include cerebral cortex, brainstem, spinal chord, pyramidal system including the upper motor neurons, extrapyramidal system, cerebellum, and the lower motor neurons in the brainstem and the spinal cord. The pyramidal motor system, also called the pyramidal tract or the corticospinal tract, start in the motor center of the cerebral cortex. There are
8197925
Non-spiking neuron


into the same neural network, but they possess specific characteristics. The major difference between these two neuron types is the manner in which encoded information is propagated along a length to the central nervous system or to some locus of interneurons, such as a neuromuscular junction. Non-spiking neurons propagate messages without eliciting an action potential. This is most likely due to the chemical composition of the membranes of the non-spiking neurons. They lack protein channels for sodium and are more sensitive to certain neurotransmitters. They function by propagating graded
16908287
Enteric nervous system


The enteric nervous system (ENS) or intrinsic nervous system is one of the main divisions of the autonomic nervous system (ANS) and consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract. It is capable of acting independently of the sympathetic and parasympathetic nervous systems, although it may be influenced by them. The ENS is also called the second brain. It is derived from neural crest cells. The enteric nervous system in humans consists of some 500 million neurons (including the various types
18349985
Grey column


), has also been linked to the lateral grey column. MSA has been shown to reduce the cell count in the lateral column by over 50%. The posterior column has a prominent role in the pain system, it is the first central relay in the nociceptive pathway. The first order afferent neuron carries sensory information to the second order neuron in the dorsal horn. The axon of the second order neuron, if it is a projection neuron and not an interneuron, then goes to the third order neuron in the thalamus
11942064
Nervous tissue


neurotransmitters are released across the synapse and bind to the post-synaptic receptors, continuing the nerve impulse. Neurons are classified both functionally and structurally. Functional classification: Structural classification: Neuroglia encompasses the non-neural cells in nervous tissue that provide various crucial supportive functions for neurons. They are smaller than neurons, and vary in structure according to their function. Neuroglial cells are classified as follows: In the central nervous system: In the peripheral nervous system: The three layers of connective tissue surrounding each nerve are: The function
20420955
Günther K.H. Zupanc


the one side, and the central elements on the other, any numerical change in the periphery prompts a corresponding numerical alteration (production or loss of neurons) in the central nervous system. He and his team also demonstrated that the continued generation of new neurons in the adult central nervous system of teleost fish is closely linked to the enormous potential of this taxon to regenerate nervous tissue and to recover behavioral function after brain lesions and spinal cord injury. By employing a proteomics approach, Zupanc and his associates performed the first large-
10776363