Ontogeny of GABA-immunoreactive cells in the prefrontal and occipital cortices of the primate.

The developmental changes in the density of total neurons and GABA-immunoreactive cells were examined in the prefrontal and occipital cortices of the crab-eating monkey, Macaca fascicularis. The density of total neurons declined rapidly during the embryonic period. Both density and proportion of GABA cells increased rapidly during the embryonic period, and only gradually increased between birth and postnatal day 30. Both density and proportion of GABA cells were higher in the occipital cortex than the prefrontal cortex between embryonic day 110 and 140, indicating late development of the prefrontal area. The activity of glutamic acid decarboxylase increases more than two times during postnatal development (HAYASHI et al., 1989), suggesting that the synthesis of GABA in each cell is enhanced during postnatal maturation.