Asunción Morán M, Reinoso-Suárez F
Departamento de Morfología, Facultad de Medicina, Universidad Autónoma de Madrid, Spain.
J Comp Neurol. 1988 Apr 1;270(1):64-85. doi: 10.1002/cne.902700107.
The topographical distribution of the cortical afferent connections to the different subdivisions of the motor cortex (MC) was studied in adult cats. The retrograde axonal transport of horseradish peroxidase technique was used. Small single injections of the enzyme were made in the entire MC, including the hidden regions in the depth of the sulcus cruciatus. The areal location and density of the subsequent thalamic neuronal labeling were evaluated in each case. Comparison of the results obtained in the various cases shows that the following: (1) The ventral anterior-ventral lateral complex is the principal thalamic source of afferents to the MC. (2) The ventral medial, dorsal medial, the different components of the posterior thalamic group (lateral, medial, and ventral posteroinferior and suprageniculate nuclei), and the intralaminar, lateral anterior, lateral intermediate, lateral medial, and anteromedial thalamic nuclei are also thalamic sites in which neural projections to the MC arise. (3) The thalamocortical projections to the MC are sequentially organized. The connections arising from the lateral part of the thalamus end in the region of area 4 that is situated medially in the superior lip of the sulcus cruciatus and in the posterior sigmoid gyrus. The projections originating in the most medial thalamic regions terminate in that region of area 6a beta which is located in the medial part of the inferior lip of the cruciate sulcus, and in the anterior sigmoid gyrus. Moreover, the ventral thalamic areas send connections to the most anteriorly located zones of the MC, while the most dorsal thalamic ones project to the most posteriorly located parts of the MC. (4) This shift in the thalamocortical connections is not restrained by cytoarchitectonic boundaries, either in the thalamus or in the cortex. (5) The populations of thalamocortical cells which project to neighboring MC subdivisions exhibit consistent overlapping among themselves. (6) These findings suggest, moreover, that the basal ganglia and the cerebellar projections to the MC through the thalamus are arranged in a number of parallel pathways, which may occasionally overlap.
在成年猫中研究了皮质传入连接至运动皮层（MC）不同亚区的拓扑分布。采用辣根过氧化物酶技术进行逆行轴突运输研究。在整个运动皮层，包括十字沟深处的隐蔽区域，进行小剂量酶的单次注射。对每种情况下随后丘脑神经元标记的区域位置和密度进行评估。对不同病例所得结果的比较显示如下：（1）腹前 - 腹外侧复合体是运动皮层传入纤维的主要丘脑来源。（2）腹内侧、背内侧、丘脑后组的不同成分（外侧、内侧、腹后下和上膝状体核）以及板内核、外侧前核、外侧中间核、外侧内侧核和前内侧丘脑核也是丘脑发出至运动皮层神经投射的部位。（3）丘脑至运动皮层的投射是按顺序组织的。丘脑外侧部分发出的连接终止于位于十字沟上唇内侧的4区区域以及后乙状回。起源于丘脑最内侧区域的投射终止于位于十字沟下唇内侧的6aβ区区域以及前乙状回。此外，丘脑腹侧区域向运动皮层最靠前的区域发出连接，而丘脑最背侧区域投射至运动皮层最后部的部分。（4）这种丘脑皮质连接的转移不受丘脑或皮层细胞构筑边界的限制。（5）投射至相邻运动皮层亚区的丘脑皮质细胞群之间存在一致的重叠。（6）此外，这些发现表明基底神经节和小脑通过丘脑至运动皮层的投射以若干平行通路排列，这些通路偶尔可能重叠。
