Geyer S, Ledberg A, Schleicher A, Kinomura S, Schormann T, Bürgel U, Klingberg T, Larsson J, Zilles K, Roland P E
Department of Neuroanatomy, Heinrich Heine University Düsseldorf, Germany.
Nature. 1996 Aug 29;382(6594):805-7. doi: 10.1038/382805a0.
The primary motor area (M1) of mammals has long been considered to be structurally and functionally homogeneous. This area corresponds to Brodmann's cytoarchitectural area 4. A few reports showing that arm and hand are doubly represented in M1 of macaque monkeys and perhaps man, and that each subarea has separate connections from somatosensory areas, have, with a few exceptions, gone largely unnoticed. Here we show that area 4 in man can be subdivided into areas '4 anterior' (4a) and '4 posterior' (4p) on the basis of both quantitative cytoarchitecture and quantitative distributions of transmitter-binding sites. We also show by positron emission tomography that two representations of the fingers exist, one in area 4a and one in area 4p. Roughness discrimination activated area 4p significantly more than a control condition of self-generated movements. We therefore suggest that the primary motor area is subdivided on the basis of anatomy, neurochemistry and function.
长期以来，哺乳动物的主要运动区（M1）在结构和功能上都被认为是均质的。该区域对应于布罗德曼细胞构筑分区第4区。有一些报告表明，猕猴以及可能人类的M1中，手臂和手部存在双重表征，并且每个子区域与躯体感觉区有独立的连接，但除了少数例外，这些报告在很大程度上未被注意到。在此我们表明，基于定量细胞构筑和递质结合位点的定量分布，人类的第4区可细分为“4区前部”（4a）和“4区后部”（4p）。我们还通过正电子发射断层扫描显示，手指存在两种表征，一种在4a区，另一种在4p区。粗糙度辨别比自我产生运动的对照条件更显著地激活了4p区。因此，我们认为主要运动区是根据解剖学、神经化学和功能进行细分的。
