Asanuma C, Thach W R, Jones E G
Brain Res. 1983 May;286(3):267-97. doi: 10.1016/0165-0173(83)90016-4.
Patterns of termination of the cerebellothalamic pathway were investigated using anterograde tracing techniques. The thalamic projections from each of the deep cerebellar nuclei are topographically organized in two and possibly in three dimensions. First, the caudo-rostral cerebellar nuclear dimension is mapped onto the mediolateral dimension within the cell-sparse ventral lateral thalamic region (VPLo, VLc, VLps, and nucleus X). By correlating this topographic ordering with the previously established lamellar organization of the cell-sparse thalamic region a somatotopy is inferred within the deep cerebellar nuclei, with caudal body parts represented anteriorly and rostral body parts represented posteriorly in each nucleus. A second topography consists of the mapping of the mediolateral dimension of the dentate and interpositus nuclei onto the ventrodorsal dimension of the lamellae in the thalamus. Since the thalamic connections with motor cortex predict a somatotopic organization with distal body parts ventral and axial parts dorsal in thalamus, each cerebellar nucleus should, therefore, represent axial body parts laterally and distal parts medially. A third mapping dimension is shown for the dentatothalamic projection: dorsal parts of the dentate nucleus project posteriorly within the cell-sparse thalamic region, and ventral parts project anteriorly. The significance of this as regards representation of the body is not known. Subsidiary foci of terminations within the cell-sparse thalamic region are visible following tritiated amino acid injections into each of the deep cerebellar nuclei. Following dentate injections these foci appear as anteroposteriorly elongated, rod-like aggregations of terminations which are similar to the rod-like aggregations of thalamocortical relay cells which have been demonstrated following focal injections of horseradish peroxidase into the motor cortex. The interpositothalamic and the fastigiothalamic terminations are elongated and appear as focal clusters in all planes of section. The interpositothalamic clusters are distributed within posterodorsally curving planar sheets. An anterograde double labeling technique, using a combination of the autoradiographic technique with the axonal degeneration technique, was used to investigate the interrelations of the terminations from different nuclei and from different parts of the same nucleus. Rods from different parts of the dentate nucleus terminate independently of one another. Dentatothalamic rods and interpositothalamic clusters, though interdigitating within the same thalamic region, do not overlap. This topographic and modular organization of the cerebellothalamic pathway suggests that the cerebellar input may reflect both the somatotopic and the columnar organization of the motor cortex.
运用顺行示踪技术研究了小脑丘脑通路的终止模式。来自每个小脑深部核团的丘脑投射在二维甚至可能在三维上呈拓扑组织。首先，小脑核团的尾 - 头维度映射到细胞稀疏的腹外侧丘脑区域（VPLo、VLc、VLps和X核）内的内外侧维度上。通过将这种拓扑排序与先前确立的细胞稀疏丘脑区域的板层组织相关联，可推断出小脑深部核团内存在躯体定位，每个核团中，身体的尾侧部分在前，头侧部分在后。第二种拓扑结构是齿状核和间位核的内外侧维度映射到丘脑板层的腹背维度上。由于丘脑与运动皮层的连接预示着一种躯体定位组织，在丘脑中远端身体部分在腹侧，轴向部分在背侧，因此每个小脑核团应该在外侧代表轴向身体部分，在内侧代表远端部分。齿状丘脑投射显示出第三种映射维度：齿状核的背侧部分在细胞稀疏的丘脑区域内向后投射，腹侧部分向前投射。这对于身体表征的意义尚不清楚。在向每个小脑深部核团注射氚标记氨基酸后，可见细胞稀疏丘脑区域内终止的附属焦点。在齿状核注射后，这些焦点表现为前后拉长的、杆状的终末聚集，类似于在向运动皮层局部注射辣根过氧化物酶后所显示的丘脑皮质中继细胞的杆状聚集。间位核 - 丘脑和顶核 - 丘脑的终末是拉长的，并且在所有切片平面上都表现为焦点簇。间位核 - 丘脑簇分布在向后背侧弯曲的平面片中。运用一种将放射自显影技术与轴突退变技术相结合的顺行双重标记技术，研究了来自不同核团以及同一核团不同部分的终末之间的相互关系。来自齿状核不同部分的杆状终末彼此独立终止。齿状丘脑杆和间位核 - 丘脑簇虽然在同一丘脑区域内相互交错，但并不重叠。小脑丘脑通路的这种拓扑和模块化组织表明，小脑输入可能反映了运动皮层的躯体定位和柱状组织。
