猫运动皮层内联合纤维末梢的电镜观察

ELECTRON MICROSCOPIC STUDY OF COMMISSURAL AXON TERMINALS IN CAT MOTOR CORTEX

本文应用顺行变性结合电镜观察方法,研究在猫运动皮层4γ区内由对侧相应皮层而来的联合纤维末梢的突触联系。实验结果表明,联合纤维末梢呈电子致密型溃变。在4γ区内共观察到92例溃变末梢,它们在第Ⅰ和第Ⅲ层内的分布几乎相等。在第Ⅲ层内还观察到1例溃变末梢与双极细胞的胞体形成直接的非对称型的突触,在第Ⅴ和第Ⅵ层内未观察到溃变末梢。在所观察到的溃变末梢中,77.2％是与树突棘形成突触,21.7％与树突梗形成突触,以及1.1％分布在胞体上,所有这些突触全是非对称型的。

Synaptic connections of commissural axon terminals from contralateral motor cortex have been studied by using anterograde degeneration and electron microscopy in the cortical area 4γ of cat. The results showed that most of the commissural terminals display electron-dense type degeneration, and 92 degenerating terminals were identified in area 4γ. The number of terminals in layer Ⅰ was nearly equal to layer Ⅲ. In layer Ⅲ, an asymmetrical synapse formed between a degenerating terminal and the soma of a bipolar cell was observed. In layers Ⅴ-Ⅵ, no degenerating terminal could be found. Among the total degenerating terminals, 77.2% were found to make synapses with dendritic spines, 21.7% made synapses with dendritic shafts and 1.1% with soma, and all of these synapses were of the assymmetrical type.