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Interneuron

 
Interneuron

 
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Interneuron
 
 
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An interneuron (also called relay neuron, association neuron or local circuit neuron) is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathway
Neural pathway

A neural pathway is a neural tract connecting one part of the nervous system with another, usually consisting of bundles of elongated, myelin-insulated neurons, known collectively as white matter....
s. Like motor neuron
Motor neuron

In vertebrates, the term motor neuron classically applies to neurons located in the central nervous system that project their axons outside the CNS and directly or indirectly control muscles....
s, interneuron cell bodies are always located in the central nervous system
Central nervous system

The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms....
 (CNS).

contrasted with the peripheral nervous system
Peripheral nervous system

The peripheral nervous system resides or extends outside the central nervous system , which consists of the brain and spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs....
 (PNS), the neurons of the central nervous system, including the brain, are all interneurons.






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An interneuron (also called relay neuron, association neuron or local circuit neuron) is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathway
Neural pathway

A neural pathway is a neural tract connecting one part of the nervous system with another, usually consisting of bundles of elongated, myelin-insulated neurons, known collectively as white matter....
s. Like motor neuron
Motor neuron

In vertebrates, the term motor neuron classically applies to neurons located in the central nervous system that project their axons outside the CNS and directly or indirectly control muscles....
s, interneuron cell bodies are always located in the central nervous system
Central nervous system

The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms....
 (CNS).

CNS

When contrasted with the peripheral nervous system
Peripheral nervous system

The peripheral nervous system resides or extends outside the central nervous system , which consists of the brain and spinal cord. The main function of the PNS is to connect the CNS to the limbs and organs....
 (PNS), 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 projection
Pyramidal cell

Pyramidal neurons are a type of neuron found in areas of the brain including cerebral cortex, the hippocampus, and in the amygdala. Pyramidal neurons are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract....
 neurons with long-distance connections). CNS interneurons are typically inhibitory, and use the neurotransmitter GABA
Gabā

Gab? or gabaa, for the Cebuano people , is the concept of a non-human and non-divine, imminent Retributive justice. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions....
 or glycine
Glycine

Glycine is the organic compound with the chemical formula NH2CH2COOH. It is the smallest of the 20 amino acids commonly found in proteins, coded by codons GGU, GGC, GGA and GGG....
. However, excitatory interneurons using glutamate also exist, as do interneurons releasing neuromodulators like acetylcholine
Acetylcholine

The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including homo sapiens....
. A human brain contains about 100 billion interneurons.

Examples of interneurons include the inhibitory interneurons in the neocortex
Neocortex

The neocortex is a part of the brain of mammals. It is the outer layer of the cerebral hemispheres, and made up of six layers, labelled I to VI ....
 which selectively inhibit sections of the thalamus
Thalamus

The thalamus is a pair and symmetric part of the brain. It constitutes the main part of the diencephalon....
 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.

In 2008, a nomenclature for the features of GABAergic cortical interneurons was proposed, called Petilla terminology.

Spinal interneurons


  • 1a Inhibitory Neuron: Found in Lamina VII. Responsible for inhibiting antagonist motor neuron
    Motor neuron

    In vertebrates, the term motor neuron classically applies to neurons located in the central nervous system that project their axons outside the CNS and directly or indirectly control muscles....
    . 1a spindle afferents activate 1a inhibitory neuron.

  • 1b Inhibitory Neuron: Found in Lamina V, VI, VII. 1b afferent or Golgi tendon organ activates it.

    Cortical interneurons


  • Parvalbumin
    Parvalbumin

    Parvalbumin is a calcium binding albumins protein with low molecular weight .It has three EF hand motifs and is structurally related to calmodulin and troponin C....
    -containing interneurons
  • CCK-containing interneurons
  • VIP-containing interneurons

    Cerebellar interneurons


  • Molecular layer interneurons (basket cell
    Basket cell

    Basket cells are inhibitory GABAergic interneurons found in several brain regions: the Cerebellum#Molecular_layer of the cerebellum, the hippocampus, and the cerebral cortex....
    s, stellate cell
    Stellate cell

    In neuroscience, stellate cells are neurons with several dendrites radiating from the cell body giving them a star shaped appearance. The three most common stellate cells are the Inhibitory postsynaptic potential interneurons found within the Cerebellum#Molecular_Layer of the cerebellum, Excitatory postsynaptic potential spiny stellate in...
    s)
  • Golgi cell
    Golgi cell

    In neuroscience, Golgi cells are Inhibitory postsynaptic potential interneurons found within the Cerebellum#Granular_Layer of the cerebellum. These Cell s synapse onto the soma of granule cells and unipolar brush cells....
    s
  • Granule cell
    Granule cell

    In neuroscience, granule cells refer to tiny neurons that are around 10 micrometres in diameter. Granule cells are found within the Cerebellum#Granular_Layer of the cerebellum, layer 4 of cerebral cortex, the dentate gyrus of the hippocampus, and in the olfactory bulb....
    s

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