The neocortex contains two neuron types, excitatory cells and inhibitory nonpyramidal (GABAergic) cells. GABAergic interneurons account for 20 - 25 % of all neocortical neurons.
Interneurons are molecularly and physiologically heterogenous and differ in terminations of their axonal endings. GABAergic interneurons also coexpress calcium-binding proteins, neuropeptidea and NOS.
Majority of neocortical interneurons derive from the ganglionic eminences of the ventral telencephalon, and tangentially migrate to the neocortex.Interneurons are engaged in neurovascular regulation and differently affected in neuropsychiatric deseases.