Interneurons

Curator: Tamas Freund. Eugene M.

Neurons are the cells that make up the brain and the nervous system. They are the fundamental units that send and receive signals which allow us to move our muscles, feel the external world, think, form memories and much more. Just from looking down a microscope, however, it becomes very clear that not all neurons are the same. So just how many types of neurons are there? And how do scientists decide on the categories?

Interneurons

Federal government websites often end in. The site is secure. Understanding brain neural circuits begins with understanding their component parts, the cells that form them. GABAergic interneurons, although a minority of cells within the brain, are critical in the control of inhibition. While understanding their diversity has been a central goal of neurobiologists, this amazing cell type has to date defied a generalized classification system. Here we review data that supports that interneuron complexity within the telencephalon can simplified by viewing them as elaborations of a much more finite group of developmentally specified cardinal classes. Within the forebrain, interneurons possess the largest diversity in morphology, connectivity, and physiological properties 1. Up until ten years ago their classification, with a few notable exceptions 2 , has remained descriptive. Moreover interneuron diversity was often treated either as a quasi continuum or a diversity space with cell types numbering potentially in the hundreds 3 , 4. The last few years of studies have coalesced into the surprising view that interneuron diversity may be fundamentally far more limited. When one considers their commonalities: at a genetic, circuit or functional level, an argument can be made for condensing large subclasses of interneurons into more finite groups. Here we suggest that based on both developmental and functional criteria interneuron diversity can be simplified and addressed experimentally. The ultimate connectivity, gene expression and physiological properties of interneurons found across the range of brain structures appear enormous Figure 1. Nevertheless we argue this complexity arises from a small number of non-overlapping cardinal classes, which represent developmental genetic ground states that possess the ability to further specialize through their later interactions with other neurons.

Demeulemeester, H.

Interneurons also called internuncial neurons , relay neurons , association neurons , connector neurons , intermediate neurons or local circuit neurons are neurons that connect to brain regions, i. Interneurons are the central nodes of neural circuits , enabling communication between sensory or motor neurons and the central nervous system CNS. Interneurons can be further broken down into two groups: local interneurons and relay interneurons. An effective means of identifying coetaneous interneurons is neuronal birthdating. In , a nomenclature for the features of GABAergic cortical interneurons was proposed, called Petilla terminology.

Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. An Author Correction to this article was published on 24 November Primates and rodents, which descended from a common ancestor around 90 million years ago 1 , exhibit profound differences in behaviour and cognitive capacity; the cellular basis for these differences is unknown. Here we use single-nucleus RNA sequencing to profile RNA expression in , individual interneurons across homologous brain regions from three primates human, macaque and marmoset , a rodent mouse and a weasel ferret.

Interneurons

Curator: Tamas Freund. Eugene M. Thomas Klausberger.

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Hestrin, S. Form, function and intracortical projections of spiny neurons in the striate visual cortex of the cat. However, some special interneurons preferentially target other interneurons. Wang B, et al. Devel Neurobio. Interneuron diversity series: molecular and genetic tools to study GABAergic interneuron diversity and function. Interneurons of the neocortical inhibitory system. About this article Cite this article Markram, H. Douglas, R. The functionally relevant classification based on afferent and efferent connectivity is easier to determine in the hippocampus, where afferent pathways and cellular compartments are confined to different laminae. Interneurons subtypes are generated from discrete proliferative regions within the subpallium On the Left side of this figure we show the progressive development of the telencephalon from being an undifferentiated epithelium to being divided up into discrete proliferative zones that produce particular interneuron populations. Developmental studies across various species 14 , 5 and systems 15 , 6 have suggested that cell diversity arises from specification programs established in progenitors modified to varying extents by their subsequent postmitotic interactions.

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The intrinsic electrophysiological properties of mammalian neurons: insights into central nervous system function. PMID Learn more. Bistratified cells fire in phase with O-LM and pyramidal cells during theta activity i. Organizing principles for a diversity of GABAergic interneurons and synapses in the neocortex. Flint, A. Reliability and state dependence of pyramidal cell-interneuron synapses in the hippocampus: an ensemble approach in the behaving rat. Journal of Neurobiology. However, if one wishes to explore the circuit properties, connectivity or computational contributions of a subclass of interneurons, one needs to consider the interplay between cardinal cells and the local cues received from the circuits they contribute to. Google Scholar Segev, I. Nat Rev Neurosci 5 , — This cell type has an axon that arborizes in perfect register with Schaffer collaterals, i. Izhikevich , Editor-in-Chief of Scholarpedia, the peer-reviewed open-access encyclopedia Reviewed by : Dr. However, interneurons are not hardwired. Bortone D, Polleux F.