Eskenasy A C, Clarke S
Institut de Physiologie, Université de Lausanne, Switzerland.
Somatosens Mot Res. 2000;17(2):123-32. doi: 10.1080/08990220050020544.
The human primary somatosensory cortex consists of four cytoarchitectonic subdivisions (3a, 3b, 1 and 2) that are likely to contain distinct somatosensory representations. The intraareal organization of these areas as well as that of the primary motor cortex (area 4) has been analyzed using histochemical stains of cytochrome oxidase, acetylcholinesterase and NADPH-diaphorase activity in normal human brains. Cytochrome oxidase activity was revealed in individual cortical neurons and neuropil. Areas 4, 3a and 3b were on average darker than areas 1 and 2. The laminar distribution of cytochrome oxidase activity varied in different areas. A prominent dark band was present in layers IV and lower III in areas 3a and 3b and in layer III in areas 1, 2 and 4. Acetylcholinesterase staining revealed fibers and pyramidal cells in layers III and V; stained layer III pyramids were rare in areas 3a and 3b and numerous in areas 1, 2 and 4. NADPH-diaphorase positive elements included Golgi-like stained non-pyramidal neurons and Nissl-like stained pyramidal neurons; the former were found, in small numbers, in layer II of areas 4, 3a, 3b and 1, and the latter in layers III and V of areas 4 and 3a and in layer V of areas 1 and 2. The dark cytochrome oxidase staining of layer IV and the paucity of acetylcholinesterase positive pyramids in areas 3a and 3b resemble the pattern found in primary visual and auditory areas, whereas the dark cytochrome oxidase staining in layer III and abundance of acetylcholinesterase positive pyramids in areas 1 and 2 that of association areas. These results suggest that the four areas included in human SI constitute hierarchical stages of cortical processing, with 3a and 3b corresponding to primary and 1 and 2 to secondary areas.
人类初级躯体感觉皮层由四个细胞构筑亚区（3a、3b、1和2）组成，这些亚区可能包含不同的躯体感觉表征。利用细胞色素氧化酶、乙酰胆碱酯酶和NADPH - 黄递酶活性的组织化学染色，对这些区域以及初级运动皮层（4区）在正常人类大脑中的区域内组织进行了分析。细胞色素氧化酶活性在单个皮层神经元和神经毡中显示出来。4区、3a区和3b区平均比1区和2区颜色更深。细胞色素氧化酶活性的层状分布在不同区域有所不同。在3a区和3b区的IV层和III层下部以及1区、2区和4区的III层有一条明显的深色带。乙酰胆碱酯酶染色显示III层和V层有纤维和锥体细胞；3a区和3b区III层染色的锥体细胞很少，而1区、2区和4区则很多。NADPH - 黄递酶阳性元素包括高尔基样染色的非锥体神经元和尼氏体样染色的锥体神经元；前者少量存在于4区、3a区、3b区和1区的II层，后者存在于4区和3a区的III层和V层以及1区和2区的V层。3a区和3b区IV层细胞色素氧化酶的深色染色以及乙酰胆碱酯酶阳性锥体细胞的稀少类似于在初级视觉和听觉区域发现的模式，而1区和2区III层细胞色素氧化酶的深色染色以及乙酰胆碱酯酶阳性锥体细胞的丰富则类似于联合区域的模式。这些结果表明，人类初级躯体感觉皮层中的这四个区域构成了皮层处理的层次阶段，3a区和3b区对应于初级区域，1区和2区对应于次级区域。
