Neostriatal cholinergic interneuron

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Neostriatal Cholinergic Interneuron is a neuron in rats, cats and possibly primates and humans (1-3).

Basic information

The Neostriatal Cholinergic Interneurons are neurons that assist with the spiny neurons to cause excitation of cortical or thalamic areas of the brain (3).

Neuronal Type: Local Interneuron

Anatomy

  • The cell body of the neostriatum cholinergic interneuron is within the neostriatum (1). The neostriatum is part of the corpus striatum, which is associated with the caudate nucleus and putamen (2).
  • They are aspiny neurons which can have somas that have a diameter in excess of 40 micrometers. The dendrites can be smooth or spiny and are usually emitted in the range of 3-6 dendrites. These dendrites do branch and can become up to a millimeter in diameter (3).
  • As stated by Schwaber, et al. the rat forebrain has about 42,000 cholinergic interneurons in it (2).

Molecular profile

  • Neurotransmitter: Dopamine and Acetylcholine (3)

Physiology

Synaptic Connections

They synapse with spiny neurons. They target medium-sized densely spiny neurons (3).

Synaptic Inputs

They receive inputs that are inhibitory and excitatory. These inputs come from spiny neurons and substantia nigra (3).

Synaptic Outputs

They have a long duration action potential, they are said to fire slowly but with regularity. These neurons have a variety of firing of action potentials, however, they mostly fire in a very tonic mode. This tonic mode of firing is how their name was enhanced to be (TAN) tonically active neuron (3). They also have outputs to GABAergic interneurons (3).

Spiking properties

After hyperpolarization, it is known that these interneurons have a slow spike because of the slow and long action potentials they have (3).


References

1. Okumura, T. et al. (2000) The cat neostriatum: relative distribution of cholinergic neurons versus serotonergic fibers. Brain and Development, 22: S27-S37.

2. Schwaber, J.S. et al. (1987) Distribution and Organization of Cholinergic Neurons in the Rat Forebrain Demonstrated by Computer-Aided Data Acquisition and three dimensional reconstruction. The Journal of Comparative Neurology, 263: 309-325.

3. Tepper, J.M., Bolam, J.P. (2004) Functional diversity and specificity of neostriatal interneurons. Current Opinion in Neurobiology, 14: 685-692.