猫大脑皮质体感Ⅰ区与Ⅱ区联系的形态学研究

THE MORPHOLOGICAL STUDY OF THE CONNECTIONS BETWEEN THE FIRST AND THE SECOND SOATOSENSORY CORTICES IN CAT

实验将HRP溶液分别注入猫大脑皮质体感Ⅰ区(SⅠ)的头面区(n=4)、前肢区(n=3)、躯干区(n=3)和后肢区(n=4)等的皮质内。观察大脑皮质体感Ⅰ区与体感Ⅰ区(SⅡ)的纤维联系。结果显示,SⅠ与同侧SⅡ、对侧SⅠ和SⅡ均存在着双向的纤维联系。这种皮质-皮质联系大多为同型的(即投射仅限于两个具有同样的体感代表区之间)。同时,也存在少量异型的联系。从SⅡ投射到同侧SⅠ的(SⅡ-SⅠ)联络神经元、从SⅠ投射到对侧SⅠ的(SⅠ-SⅠ)和从SⅡ投射到对侧SⅠ的(SⅡ-SⅠ)连合(胼胝体)神经元多分布于皮质Ⅵ层,其次为Ⅲ层。SⅠ与同侧丘脑的板内核、腹后核和后核也存在纤维联系。研究资料表明,SⅠ与SⅡ间及它们与丘脑间存在着双向的纤维联系,因此,两区之间的联系存在两条径路,即直接的皮质-皮质通路和间接的皮质-丘脑一皮质通路。

In 14 cats the HRP solution was injected into the first somatosensory cortices which were considered as the representations of the head and the face (n= 4). the forelimb (n = 3), the trunk (n-3) and the posterior limb (n = 4), for observation of the connections between the first (S Ⅰ ) and the second (S Ⅱ ) somatosensory cortices. The results from these experiments provide that there are widely anterograde and retrograde connections between the area S Ⅰ and the ipsilateral SⅡ , the contralateral S Ⅰ and the S Ⅱ . The most associative connections are homotypic representation, and a little of that are heterotypical connections. The S Ⅰ -S Ⅱ associative neurons the S Ⅰ -S Ⅱ and the S Ⅱ -S Ⅰ commissural neurons present mostly in the layer (IV), some are in the layer Ⅲ. The neurons in the S Ⅰ also connect with the ventral posterior, the intralaminar nauclei and the posterior group of the thalamus. According to the results of these experiments, there are two pathways of connection the area S I with the area S Ⅱ. One is the direct corticocortical connections, the other is indirect cortico-thalamo-cortical connections.