THE DEVELOPMENT OF STRUCTURE AND FUNCTION IN THE POSTNATAL HUMAN CEREBRAL CORTEX FROM BIRTH TO 72 MONTHS: CHANGES IN THICKNESS OF LAYERS II AND III CO-RELATE TO THE ONSET OF NEW AGE-SPECIFIC BEHAVIORS

Abstract

Hypothesis: The thickness of a cortical layer is a composite measure of neuronal, axonal, dendritic, synaptic, and glial numbers and sizes that may relate to the function of a cortical area. Methods: 35 age-specific behaviors with defined cortical localization whose onset lies between birth and 72 months were selected. Each behavior's function localized to one or more of 12 cytoarchitectonic areas (Brodmann areas 4, with homuncular subdivisions for leg, trunk, face, and hand, plus 17, 18, 19, 20, 21, 24, 36, and 37). Data on cortical thickness for each layer of 41 cytoarchitectonic areas (including the 12 above) of the postnatal human cerebral cortex from birth of 72 months were analyzed for general patterns of change. For the 12 cortical areas functionally related to the age-specific behaviors, we searched for layer thickness changes that co-related to when the behaviors began. Results: Without exception, all layers of the 41 cortical areas of the postnatal human cerebral cortex studied develop through a...