Dendritic bundling in layer I of granular retrosplenial cortex: intracellular labeling and selectivity of innervation.
Dendritic bundling in layer I of granular retrosplenial cortex: intracellular labeling and selectivity of innervation.
复制标题
颗粒压后皮质第一层树突状成束：细胞内标记和神经支配的选择性。
DOI：
10.1002/cne.902950104
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Sripanidkulchai,K
中科院分区：
文献类型：
--
作者：
Wyss,JM;VanGroen,T;Sripanidkulchai,K
脾后皮层内外的外在投射已被详细研究，但该区域内的内在回路尚未被完全描述。为了进一步确定内部联系，将少量的逆行荧光示踪剂氟金注射到大鼠的脾后皮层。这些注射标记了对侧同位皮层第II - V层的神经元。在III - V层中，标记的神经元存在于比注射部位大得多的区域，但在II层中，神经元以非常精确的同位模式标记。注射后，只有第II层的神经元显示出高度标记的顶端树突，这些标记的树突在皮层的Ic层和Ib层形成紧密的束状结构，并在Ia层扩散。高尔基染色材料的检查表明，第II层的大多数神经元是小锥体细胞，具有2-3个小的基树突和一个大的尖树突，在第i层广泛分布。为了验证第II层神经元的结构，它们在细胞内充满了路西法黄。对这些标记细胞的检查证实了高尔基染色材料的观察结果，并表明许多第II层细胞的根尖树突呈明显的角度，显然是为了加入一个束和/或避免束间的空间。束示迹实验表明，丘脑前腹侧核似乎选择性地投射到包含树突束的区域，而皮层内的投射似乎终止于树突束之间30-200 μm的Ib层和Ic层。此外，包含束的区域显示密集的AChE染色，但束间空间几乎没有AChE染色。这些发现表明，树突束的一种形式是输入和输出特异性的，可能在丘脑输入到扣带皮层的调节中发挥重要作用。
The extrinsic projections to and from the retrosplenial cortex have been studied in detail, but the intrinsic circuitry within this region has been characterized less completely. To further define the internal connections, small injections of the retrograde, fluorescent tracer Fluorogold were made into the retrosplenial cortex of the rat. These injections label neurons in layers II‐V of the contralateral homotopic cortex. In layers III‐V, the labeled neurons are present over an area much larger than the injection site, but in layer II neurons are labeled in a very precise homotopic pattern. Following these injections, only the neurons in layer II display heavily labeled apical dendrites, and these labeled dendrites form tight bundles in layer Ic and Ib of the cortex and spread out in layer Ia. An examination of Golgi‐stained material demonstrates that most of the neurons in layer II are small pyramidal cells with 2–3 small basal dendrites and a single, large apical dendrite that arborizes extensively in layer Ia. To verify the structure of the layer II neurons, they were intracellularly filled with Lucifer yellow. Examination of these labeled cells confirms the observations from the Golgi‐stained material and demonstrates that many apical dendrites of the layer II cells angle acutely, apparently to join a bundle and/or avoid an interbundle space. Tract tracing experiments demonstrate that the anteroventral nucleus of the thalamus appears to project selectively to the region containing the dendritic bundles, whereas intracortical projections appear to terminate in layers Ib and Ic in the 30–200 μm spaces between the bundles. Furthermore, the areas containing the bundles display dense AChE staining, but the interbundle spaces are almost free of AChE staining. These findings demonstrate a form of dendritic bundling that is input and output specific and may play an important role in the regulation of thalamic inputs to the cingulate cortex.