engleski

Intensive perinatal dendritic growth on large pyramidal neurons in the human prefrontal cortex shows layer specific pattern

In this study we have quantitatively analyzed development of dendritic tree of large layer IIIC (L3N) and layer V pyramidal neurons (L5N) in the human prefrontal cortex (PFC) impregnated by Golgi method in period from 17 week of gestation (wg) up to third month postnatal. At 17wg both classes of neurons were immature showing similar dendritic morphology. Period between 17-26wg was characterized by protrusion of primary dendrites in basal and apical part of dendritic tree, without change in the length and in the number of segments. After 26wg no further increase in number of primary dendrites could be observed. The phase of rapid growth of basal dendritic tree begins with an outgrowth of new dendritic segments (stage1), followed by their large elongation without significant formation of new dendrites (stage2). Stage1 occurred between 26-32wg for L5N and between 36wg-1m for L3N. Stage2 occurred between 32wg-1m for L5N and newborn-3m for L3N. By the 3rd postnatal month L5N attained 80% and layer L3N 60% of the total adult size of their dendritic trees and both classes of neurons already displayed an adult-like overall morphological dendritic phenotype. Phase of intensive dendritic growth coincides with the massive ingrowth of afferent fibers into the cortical plate ; around 26wg for L5N with thalamo-cortical, and around 36wg for L3N with cortico-cortical axons entrance. Such an early functioning neural network may represent a neurobiological basis for initial cognitive functions already present in newborns and young infants.

prefrontal cortex; pyramidal neurons; perinatal; human

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