Interneurons

Question 1

What is another term for inhibitory neurons, and where are they more abundant?

Answer 1

Inhibitory neurons are also called “interneurons.” They are more abundant in the CNS than in the PNS, constituting about 20-30% of all neurons in the neocortex.

Question 2

How are interneurons classified in the neocortex, and what are the four main subtypes based on?

Answer 2

In the neocortex, interneurons are classified into four main subtypes based on the expression of Parvalbumin, Cholecystokinin (CCK), Vasoactive Peptide (VIP), and somatostatin (SOM).

Question 3

What are the two types of inhibitory input pathways for interneurons, and how are they defined?

Answer 3

1. Feed-forward inhibition: If interneurons receive excitatory input from neurons located outside their region.
2. Feed-back inhibition: If interneurons are innervated by the cells they, in turn, innervate (close to them)

Question 4

What are the major functional roles of interneurons in neural circuits?

Answer 4

1. Gating the inputs and output of principal cells
2. Controlling the activity level of the brain area
   3.Coordination and generation of rhythmic discharge: