The emergence of the cortical GABAergic neuron: with particular reference to some peptidergic subpopulations.

The technical developments which have led to our present ability to make predictions about neurochemical identity from morphological observations are retraced with particular reference to the GABAergic neuron and its many subdivisions. The synaptology of four peptidergic sub-populations in the cerebral cortex is examined and described in detail. It is concluded that the recognition of Gray Type 1 and Type 2 synapse types continues to provide a key element in our analysis and understanding of the connectivity of the CNS.