大鼠海马-小脑皮层-小脑深部核团投射的电生理学和HRP研究

HIPPOCAMPUS-CEREBELLAR CORTEX-CEREBELLAR NUCLEI PROJECTION IN THE RAT: ELECTROPHYSIOLOGICAL AND HRP STUDIES

本文用电生理学和HRP示踪法,研究了大鼠海马-小脑皮层投射的空间分布,小脑皮层的海马投射区与其深部核团间的纤维联系。 电生理学的实验结果表明,刺激背侧海马CA_1/CA_3区,均可使小脑皮层第Ⅵ小叶的浦肯野细胞产生顺行多突触的诱发简单锋电位和复杂锋电位反应。提示背侧海马CA_1/CA_3区与小脑皮层之间有经苔状纤维和攀缘纤维的多突触投射。实验证明,大鼠的这一投射的终止区域,集中在小脑皮层第Ⅵ小叶中线外侧0.8—1.4mm的范围内;并且来自CA_1区的投射以对侧性为主,CA_3区的投射以同侧性为主。HRP示踪的实验表明,背侧海马CA_1/CA_3区在小脑皮层第Ⅵ小叶的投射区是小脑纵区组构的间位区,该区皮层与间位核之间存在着交互投射关系。

The spatial distribition of the hippocampus-cerebellar projection and the connection between the projection area of hippocampus in the cerebellum and cerebellar nuclei were studied by means of electrophysiological and HRP labelling techniques.Polysynaptic responses of Purkinje cell's simple and complex spike in the lobule Ⅵ could be evoked by stimulation of the area CA_1/CA_3 of the dorsal hippocampus. These results suggest that there are polysynaptic projections from CA_1 and CA_3 areas of dorsal hippocampus to the lobule Ⅵ of cerebellar cortex, and the last relay fibers for these projections are mossy fiber and/or climbing fiber. It is also shown that this hippocampus-cerebellar projection predominantly terminates at the lobule Ⅵ of cerebellar cortex, 0.8—1.4mm lateral to the midline. The projection from CA_1 area is mainly contralateral, whereas the projection from CA_3 area is mainly ipsilateral.The results with HRP labelling indicate that the projection area of hippocampus is an interpositus zone of the lobule Ⅵ. Reciprocal connections may exist between this cortical area and the interpositus nucleus.