RADIAL ORGANIZATION OF THALAMIC PROJECTIONS TO THE NEOCORTEX IN THE MOUSE
RADIAL ORGANIZATION OF THALAMIC PROJECTIONS TO THE NEOCORTEX IN THE MOUSE
复制标题
DOI：
10.1002/cne.901940206
复制
发表时间：
1980-01-01
影响因子：
2.5
通讯作者：
CAVINESS, VS
中科院分区：
文献类型：
--
作者：
FROST, DO;CAVINESS, VS
通过顺行变性方法研究了小鼠丘脑投射到大量新皮质区域的皮质内分布。终止丘脑轴突的基本径向分布在整个小鼠皮质中是均匀的，并且与其他哺乳动物物种中遇到的基本相同。终止轴突集中在 3 层：第一层中的外层、第四层和/或第三层中的中间层以及第六层中的内层。在大多数视野中，终止轴突在某种程度上延伸到第五层。不同视野会遇到变化，特别是在突起的密度和发散程度以及各个层相对于细胞结构层的径向范围方面。根据其他研究，丘脑对每个区域的投射似乎由 2 个一般轴突类别组成。 I 类轴突密集地终止于中间层，似乎口径较大，并且通常有通往其他层的侧支。 II 类轴突并不密集地终止于中间层，并且似乎口径较小。终止II类轴突可以分布到1层或多层并且可以集中在内层和/或外层。丘脑向每个区域的投射都起源于多个核。所有投射到新皮质的丘脑核似乎都具有 II 类投射，许多具有 I 类投射。与许多细胞核中不同位置的病变相关的皮层退化模式表明，丘脑中继神经元是沿着投影线组织的，同一线中的神经元投影到相同的切向限制的皮层区域。 I 类和 II 类轴突起源的神经元沿着投影线混合。
The intracortical distributions of the thalamic projections to a large number of neocortical fields were studied by the anterograde degeneration method in the mouse. The basic radial distribution of terminating thalamofugal axons is uniform throughout the mouse cortex and is essentially the same as that encountered in other mammalian species. Terminating axons are concentrated in 3 tiers: an outer tier in layer I, a middle tier in layers IV and/or III and an inner tier in layer VI. In most fields, terminating axons extend, to some extent, into layer V. Variations are encountered from field to field, particularly in the density and degree of divergence of projections and in the radial extent of individual tiers with respect to cytoarchitectonic layers. In accordance with other studies, the thalamic projections to each field appear to be composed of 2 general axon classes. Class I axons terminate densely in the middle tier, seem to be of large caliber and often have collaterals to the other tiers. Class II axons do not terminate densely in the middle tier and seem to be of small caliber. Terminating class II axons may be distributed to 1 or more tiers and may be concentrated in the inner and/or outer tiers. The thalamic projection to each field has its origin in multiple nuclei. All thalamic nuclei projecting to the neocortex appear to have class II projections and many have class I projections. Patterns of degeneration in the cortex associated with lesions in different positions in many nuclei suggest that thalamic relay neurons are organized along lines of projection, neurons in the same line projecting to the same tangentially restricted cortical region. The neurons of origin of class I and class II axons are intermixed along the lines of projection.