Search results
Results From The WOW.Com Content Network
However, excitatory interneurons using glutamate in the CNS also exist, as do interneurons releasing neuromodulators like acetylcholine. In addition to these general functions, interneurons in the insect CNS play a number of specific roles in different parts of the nervous system, and also are either excitatory or inhibitory.
The two main neuronal classes in the cerebral cortex are excitatory projection neurons (around 70-80%) and inhibitory interneurons (around 20–30%). [2] Neurons are often grouped into a cluster known as a nucleus where they usually have roughly similar connections and functions. [3] Nuclei are connected to other nuclei by tracts of white matter.
Basket cells are multipolar GABAergic interneurons that function to make inhibitory synapses and control the overall potentials of target cells. In general, dendrites of basket cells are free branching, contain smooth spines, and extend from 3 to 9 mm. Axons are highly branched, ranging in total from 20 to 50mm in total length.
Rosehip cells, unique human inhibitory neurons that interconnect with Pyramidal cells; Renshaw cells, neurons with both ends linked to alpha motor neurons; Unipolar brush cells, interneurons with unique dendrite ending in a brush-like tuft; Granule cells, a type of Golgi II neuron; Anterior horn cells, motoneurons located in the spinal cord
The Golgi type II cells might be excitatory or inhibitory interneurons, or they can be both. Golgi type II cells function as inhibitory interneurons, which could produce response patterns that make the primary neurons more responsive to the beginning of stimuli and to temporal variations in the afferent input.
In addition, Renshaw cells make inhibitory connections to several groups of motor neurons, Ia inhibitory interneurons as well as the same motor neuron that excited them previously. [13] Furthermore, the connection to the motor neurons establishes a negative feedback system that may regulate the firing rate of the motor neurons. [13]
Granule cells are subject to feed-forward inhibition: granule cells excite Purkinje cells but also excite GABAergic interneurons that inhibit Purkinje cells. Granule cells are also subject to feedback inhibition: Golgi cells receive excitatory stimuli from granule cells and in turn send back inhibitory signals to the granule cell. [13]
Renshaw cells are inhibitory interneurons found in the gray matter of the spinal cord, and are associated in two ways with an alpha motor neuron. They receive an excitatory collateral from the alpha neuron's axon as they emerge from the motor root, and are thus "kept informed" of how vigorously that neuron is firing. They send an inhibitory ...