Postnatal Development of Dendritic Structures in the Medial Prefrontal Cortex of the Marmoset

Tetsuya Sasaki1, Aoi Hirosato1,2; Oga, Tomofumi1,2; Fujita, Ichiro2,3; , Ichinohe, Noritaka1,4

1Dept of Ultrastruc Study, Nat Inst of Neurosci, NCNP, Tokyo, Japan; 2Grad Sch. Frontier Biosciences, Osaka Univ, Osaka, Japan; 3CiNet, Nat Inst of Information and Communications Technology, Osaka Univ, Osaka, Japan; 4Lab for Molecular Analysis of Higher Brain Func, RIKEN, BSI


In the primate cerebral cortex, dendritic spines rapidly increase in number after birth up to infancy or mid-childhood, and then decrease towards adulthood. Abnormalities in these processes accompany several psychiatric disorders. In this study, we examined developmental changes of basal dendrites and spines of layer III pyramidal cells in the medial prefrontal cortex (mPFC) of the common marmoset. The mPFC consists of several areas with distinct features in layer organization, histochemistry, connections, and, in humans, vulnerability to psychiatric disorders. We selected three areas for examination: granular dorsomedial prefrontal (area 9), dysgranular ventromedial prefrontal (area 14r, and agranular anterior cingulate (area 24) cortices. Dendritic field areas, lengths, number of branching points, and total spine number reached a peak at 23 postnatal months in all three areas. However, the profiles of spine formation and pruning differed across the three areas with different degrees of granularity; the amount of spine loss from the peak to adulthood was less in areas 24 (33%) and 14r (29) than in area 9 (43). Disturbance of this modest spine pruning in the less

granular cortical areas may lead to an excessive loss of spines reported for areas 24 and 14r of schizophrenic patients.