Tanaka D, Sakai S T, Górska T
J Comp Neurol. 1983 Feb 10;214(1):17-31. doi: 10.1002/cne.902140103.
Corticothalamic projections from postcruciate area 4, located on the rostral part of the posterior sigmoid gyrus, were traced with the autoradiographic technique in the dog. Injections of tritiated amino acids were made into the lateral and medial parts of area 4 in regions corresponding to the forelimb and hindlimb areas of the primary motor cortex, respectively. In cases with injections placed in the lateral part of area 4, dense accumulations of label were present in the lateral part of the ventral anterior nucleus (VA), the central part of the ventral lateral nucleus (VL), the ventral half of the ventral posterior inferior nucleus (VPI), the caudal part of the central lateral nucleus (CL), and the centrum medianum (CM). Lighter label was also present in the lateral part of the cytoarchitectonically distinct VL region bordering the ventrobasal complex (VB), as well as in the ventrolateral part of the mediodorsal nucleus (MD), and in the lateral posterior nucleus (LP). In one case in which the injection site involved an adjacent part of area 3a, label was also seen ventrally in the medial division of the posterior nuclear group (POm). However, no detectable differences in VL, MD, or intralaminar labeling patterns were noted between this case and the four other cases with injections confined to the lateral part of area 4. In two cases with injections restricted to the medial part of area 4, dense label was present in the lateralmost part of VL, the ventral part of VPI, the caudal part of CL, and CM. Lighter label was also present in the VL region bordering the dorsolateral edge of VB and in LP. An additional case in which the injection also involved the rostral border of area 3a showed a similar pattern of thalamic labeling. Projections from both the lateral and medial parts of area 4 were also noted in the subthalamic nucleus, zona incerta, and nucleus of Darkschewitsch. These results suggest that corticothalamic projections from postcruciate area 4 to VL are organized topographically such that projections from the lateral part of area 4 project centrally within VL while those from the medial part of area 4 project more laterally. Both parts of area 4 also project topographically to a cytoarchitectonically distinct region of VL located immediately adjacent to VB. In contrast, the projections to the intralaminar nuclei do not appear to be topographically organized. The data from cases involving spread of the injection into area 3a suggest that projection patterns from area 3a to ventral, intralaminar, and medial thalamic nuclei are similar to those from area 4. However, it appears that at least the lateral part of area 3a also projects to POm.
采用放射自显影技术在犬身上追踪了位于后乙状回吻部的十字后区4的皮质丘脑投射。分别将氚标记氨基酸注射到4区对应于初级运动皮层前肢和后肢区域的外侧和内侧部分。在将注射部位置于4区外侧部分的情况下，腹前核（VA）外侧部分、腹外侧核（VL）中央部分、腹后下核（VPI）腹侧半、中央外侧核（CL）尾侧部分以及中央中核（CM）出现密集的标记积累。在与腹侧基底复合体（VB）相邻的细胞构筑学上不同的VL区域外侧部分、背内侧核（MD）腹外侧部分以及外侧后核（LP）也有较淡的标记。在一例注射部位涉及3a区相邻部分的病例中，在后核群内侧部（POm）腹侧也可见标记。然而，该病例与其他四例注射局限于4区外侧部分的病例相比，在VL、MD或板内核标记模式上未发现可检测到的差异。在两例注射局限于4区内侧部分的病例中，VL最外侧部分、VPI腹侧部分、CL尾侧部分和CM有密集标记。在与VB背外侧边缘相邻的VL区域以及LP也有较淡的标记。另一例注射还涉及3a区吻侧边界的病例显示出类似的丘脑标记模式。在丘脑底核、未定带和达克谢维奇核中也注意到了4区外侧和内侧部分的投射。这些结果表明，十字后区4至VL的皮质丘脑投射在地形上是有组织的，使得4区外侧部分的投射在VL内投射到中央，而4区内侧部分的投射更偏向外侧。4区的两个部分在地形上也投射到紧邻VB的细胞构筑学上不同的VL区域。相比之下，向板内核的投射似乎没有地形组织。涉及注射扩散到3a区的病例数据表明，3a区向腹侧、板内和内侧丘脑核的投射模式与4区相似。然而，似乎至少外侧部分的3a区也投射到POm。
