인태아대뇌 연상회부(Brodmann 제40피질분야) 피질의 발육 및 세포구축학적 연구

Abstract

The authors have made a study of the quantitative changes in the early development of human brain with special reference to the growth and the cytoar• chitectonics of cerebral cortex in the supramarginal gyrus (Brodmanns area 40) in a sample of 122 Korean fetal brains (67 of mιIe and 55 of female) of which the age ranged from 5th month to comp letion of fetal life , The summary of the findings is as follows: 一 1. The average thickness of cerebral cortex in fetal age of 5 months was estimated at 0.75mm, and its growth pattern showed a rather rapid until the 7th month of fetal age , and thereafter with a relatively slower rate, it reached at mean value of 1. 62 mm in the age of 10th month. The thickness of cortex was measured at 0.73 mm on the average for the brain with the weight of less than 50gm, and the relation between the thickness of cortex and the weight of brain showed that the development of cortex in thickness was rather rapid in growth rate as the weight of brain increased up to the level of 151-200 gm, and then it developed relatively slowly as the brain got heavier reaching at the mean value of 1.67mm in thickness when the brain got weight of more than 401 gm. 2. The differentiation of the lamination of cerebral cortex was found to begin in earlier part of 6th month of the fetal age (21st week of the ge • station period) or, in terms of the brain weight when it reached at 41.6 gm. 3. The absolute cell density of cerebral cortex was found to increase with fetal age until 7t h month at which the density became maximum, and thersafte' it started to decrease gradually as the fetus ages. As for the relationship between the absolute cell density and the brain weight, the highest mean value of density was of brain weighing 101-150 gm , and thereafter it showed a gradual decrease. 4. It seemed that the nerve cells of cerebral cortex might be increasing in number rapidly until the 7th month of fetal life , and after that the number of nerve cells would not increase sub• stantially. 5. The sexual difference could be observed neither in the thickness of cortex nor in the relative and the absolute cell densities.