Regional differences in synaptogenesis in human cerebral cortex

The formation of synaptic contacts in human cerebral cortex was compared in two cortical regions: auditory cortex (Heschl’s gyrus) and prefrontal cortex (middle frontal gyrus)…. Synaptogenesis and synapse elimination in humans appear to be heterochronous in different cortical regions and, in that respect, appears to differ from the rhesus monkey, where they are concurrent. In other respects, including overproduction of synaptic contacts in infancy, persistence of high levels of synaptic density to late childhood or adolescence, the absolute values of maximum and adult synaptic density, and layer specific differences, findings in the human resemble those in rhesus monkeys.

Abstract. The Journal of comparative neurology 1997; 387(2):167-78