인태아대뇌 연상회부(Brodmann 제18피질분야) 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 parastriate area (Brodmanns are' 18) in a sample of 98 korean fetal brains (51 of male & 47 of female) of which the age ranged from 5th month to completion of fetal life. The summary of the findings is as follows:- 1. The average thickness of cerebral cortex in fetal age 5 months was estimated at O.5mm, and - 309 its growth pattern showed a rather rapid until the 7th month of fetal age, and thereafter with a reI atively slower rate, it reached at mean value of 1.42 mm in the age of 10th month. The thickness of cortex was measured at O.5mm on the average for the brain with the weight of less than 5Ogm, 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 101-150gm, and then it developed relatively slowly as the brain got weight of 351gm and there• after it developed rather rapidly reaching at the mean value of 1.36mm in thickness when the hrain got the weight of more than 401gm, 2. The differentiation of the lamination of cerebral cortex was found to begin in the later part of 6th month of fetal age or, in terms of the brain weight when it reached at 71. 8gm, 3. The ahsolute cell density of cerebral cortex was found to increase with fetal age until 7th month at which the density became masimum, and there after it started to decrease gradually as the fetus age. As for the relationship between the absolute cell density and the brain weight, the highest mean value of density was of brain weighing 101-150gm, 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 substantially. 5. The sexual difference could be observed neither in the thickness of cortex nor in the relative and the absolute cell densities.