Interneuron 988337 224582967 2008-07-09T14:55:18Z Jannisri 5511880 {{Infobox Anatomy | Name = {{PAGENAME}} | Latin = | GraySubject = | GrayPage = | Image = ReflexArc1.jpg | Caption = The mechanism of the [[reflex arc]]. (Relay neuron labeled at right center. Diagram discusses the PNS definition.) | Image2 = | Caption2 = | Precursor = | System = | Artery = | Vein = | Nerve = | Lymph = | MeshName = Interneurons | MeshNumber = A08.663.358 | DorlandsPre = i_10 | DorlandsSuf = 12455676 | }} An '''interneuron''' (also called '''association neuron''' or '''bipolar neuron''') is a sensory neuron in neural pathways. Like the [[motor neuron]]s their bodies cells are always located in the [[central nervous system]] (CNS) which connects the afferent neuron and efferent neuron. ==CNS== According to the [[peripheral nervous system]] (PNS) definition, the neurons of the central nervous system, including the brain, are all interneurons. However, in the CNS, the term '''interneuron''' is used for small, locally projecting neurons (in contrast to larger [[Pyramidal cell|projection]] neurons with long-distance connections). CNS interneurons are typically inhibitory, and use the neurotransmitter [[GABA]] or [[glycine]]. However, excitatory interneurons using [[glutamate]] also exist, as do interneurons releasing neuromodulators like [[acetylcholine]]. A human brain contains about 100 billion interneurons. Examples of interneurons include the [[inhibitory interneuron]]s in the [[neocortex]] which selectively inhibit sections of the [[thalamus]] based on synaptic input both from other parts of the neocortex and from the thalamus itself. This is theorized to help focus higher attention on relevant sensory input and help block out behaviorally irrelevant or unchanging input, such as the sensation of the backs of your thighs on a chair. The neurophysiological measure short-latency intracortical inhibition (SICI) is believed to be mediated by these [[inhibitory interneurons]].{{Fact|date=February 2008}} In 2008, a nomenclature of features of GABAergic cortical interneurons was proposed, called ''Petilla terminology''.<!-- --><ref name="pmid18568015">{{cite journal |author=Ascoli GA, Alonso-Nanclares L, Anderson SA, ''et al'' |title=Petilla terminology: nomenclature of features of GABAergic interneurons of the cerebral cortex |journal=[[Nat. Rev. Neurosci.]] |volume=9 |issue=7 |pages=557–68 |year=2008 |month=July |pmid=18568015 |doi=10.1038/nrn2402 |url=http://dx.doi.org/10.1038/nrn2402}}</ref> === Spinal interneurons === <LI> 1a Inhibitory Neuron: Found in Lamina VII. Responsible for inhibiting antagonist [[motor neuron]]. 1a spindle afferents activate 1a inhibitory neuron. <LI> 1b Inhibitory Neuron: Found in Lamina V, VI, VII. 1b afferent or Golgi tendon organ activates it. === Cortical interneurons === <LI> [[Parvalbumin]]-containing interneurons <LI> CCK-containing interneurons <LI> VIP-containing interneurons === Cerebellar interneurons === <LI> Molecular layer interneurons ([[basket cell]]s, [[stellate cell]]s) <LI> [[Golgi cell]]s <LI> [[Granule cell]]s == References == {{reflist|2}} ==External links== * {{eMedicineDictionary|Interneurons}} {{neuroanatomy-stub}} {{Spinal cord}} {{Nervous tissue}} [[Category:Neurons]] [[de:Interneuron]] [[fr:Interneurone]] [[nl:Interneuron]] [[pl:Interneuron]] [[ru:Вставочный нейрон]]