인태아 대뇌중신전회피질(제4차질분야)의 발육 및 세포구조학적 연구

Abstract

Authors studied on the development and cytoarchitectonics of the cerebral cortex in the Brodmann's area of 4 in the precentral gyrus of the 125(67 male, 58 female) Korean fetal brains and summarized the results as follows; 1. The thickness of the cerebral cortex was very thin of 194 micra at the fourth month of the fetal age and increased very rapidly until the sixth month, relatively rapidly until the seventh month, very slowly until the ninth month and thereafter very rapidly. As the relation of the brain weight, up to 150gm of brain weight, it increased very rapidly, up to 400 gm of brain weight increased very slowly and thereafter it increased very rapidly again. 2. The differentiation of the lamination of the cerebral cortex began at the sixth' fetal month (22nd week of the gestation period) and during the seventh fetal month the lamination of the cortex had almost occurred but even at the end of the seventh month there was some undifferentiated cortex and so there might be a great individual difference of lamination. 3. The cell density of the cerebral cortex was very high during fifth and sixth fetal months and thereafter it decreased gradually as the fetal age increased. As the relation of the cell density with the brain weight, the cell density was very high up to 150gm of brain weight and thereafter it decreased gradually as the brain weight increased. 4. The nerve cells of the fetal cortex might be increased very rapidly up to the seventh month of the fetal age and thereafter the number of the nerve cells of the cortex might be stabilized. 5. Thickness of the cortex, the relative cell density and absolute cell density of the cerebral cortex had no sexual difference.