LAMINAR DISTRIBUTION OF NEUROPEPTIDE Y-IMMUNOREACTIVE NEURONS IN HUMAN PREFRONTAL CORTEX DURING DEVELOPMENT

Neuropeptide Y (NPY) is present in neurons of the adult human cerebral cortex. In view of the reported roles of NPY in the central nervous s ystem in health and during certain disease conditions, we have studied normal development of NPY immunoreactivity (-ir) in the human prefron tal cortex (PFC), Brodmann areas 9 and 46. Twenty-six specimens rangin g from the ages of 14 postovulatory weeks to 34 years exhibited patter ns that revealed six periods in the development of the laminar distrib ution and density of NPY-ir neurons. Changes during prenatal and perin atal periods reflect the onset, development, and resolution of the tra nsient fetal telencephalic compartments, including the subplate zone, in which NPY-ir neurons are especially abundant. Before the age of 1 y ear, the majority of NPY-ir neurons were found in the subplate zone, w hereas, after 1 year, the majority were seen in the cortical layers. T his is in contrast with the human visual cortex, where the majority of NPY-ir neurons were still located in the white matter. The density of cortical NPY-ir neurons increased in the fifth developmental period ( ages 4-7 years), coinciding with the increase of cortical volume and m arked progression of cognitive functions. The adult pattern of a relat ively low density of cortical NPY-ir neurons was reached in period 6 ( from about 8 years), when individual variation also became apparent. O ur data point to a protracted maturation of NPY-ir in the human PFC an d to different distribution patterns of NPY-ir neurons in different co rtical areas. (C) 1997 Wiley-Liss, Inc.