Corticotectal and corticothalamic efferent projections of SIV somatosensory cortex in cat.
Corticotectal and corticothalamic efferent projections of SIV somatosensory cortex in cat.
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猫 SIV 体感皮层的皮质顶盖和皮质丘脑传出投射。
DOI：
10.1152/jn.1983.50.4.896
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发表时间：
1983
影响因子：
2.5
通讯作者：
Edwards,SB
中科院分区：
文献类型：
--
作者：
Stein,BE;Spencer,RF;Edwards,SB
用放射自显影和辣根过氧化物酶的轴突运输方法，在猫的前外侧裂沟（AES）的皮质中发现了大量的皮质顶盖（和皮质丘脑）投射。皮质-顶盖投射几乎完全来自于第五层中的中-大锥体细胞。AES的致密投射区域之一是其上级银行的喙侧，最近已证实了第四躯体位置表示（SIV）。它终止于体细胞所在的上级丘的中层和深层。该通路是双侧的，但同侧比对侧重得多。与SIV和邻近组织的大量皮质顶盖投射相反，没有明确的证据表明传统体感皮质SI-SIII的皮质顶盖投射。这一发现，即猫上级丘的体感投射来自SI-SIII以外的区域，是出乎意料的基础上，什么是已知的视觉皮质-顶盖的预测。然而，这是与其他皮质的预测，终止于该结构的中间和深层的模式，并与可证明的皮质顶盖的影响，从SI到SIII在这个动物的情况下是一致的。这些数据与其他研究人员的证明相反，即啮齿类动物的SI皮质存在皮质-顶盖投射。显然，在下行躯体感觉通路的组织方面存在着根本的物种差异。还观察到AES的皮质丘脑投射。这种下降的投影似乎形成了一个外壳的标记细胞和纤维周围的ventrobasal复合体，但明确的终端标记内的ventrobasal复合体不能证明。致密的终端标记是明显的丘脑核（PO）的丘脑皮质传入AES起源的后组。
Substantial corticotectal (and corticothalamic) projections from the cortex of the anterior ectosylvian sulcus (AES) were demonstrated in the cat using the axonal transport methods of autoradiography and horseradish peroxidase. The corticotectal projection arises nearly exclusively from medium-large pyramidal cells in lamina V. One of the densest projecting areas of the AES is the rostral aspect of its superior bank, where a fourth somatotopic representation (SIV) has recently been demonstrated. It terminates in the intermediate and deep laminae of the superior colliculus, where somatic cells are located. The pathway is bilateral but much heavier ipsilaterally than contralaterally. In contrast to the substantial corticotectal projection from SIV and adjacent tissue, there was no unequivocal evidence for a corticotectal projection from traditional somatosensory cortex SI-SIII. This finding, that somatosensory projections to the cat superior colliculus arise from an area outside of SI-SIII, was unexpected on the basis of what is known about visual corticotectal projections. However, it is consistent with the patterns of other cortical projections that terminate in the intermediate and deep laminae of this structure and with the absence of demonstrable corticotectal influences from SI to SIII in this animal. These data are in contrast to demonstrations by other investigators that there is a corticotectal projection from SI cortex in rodents. Apparently there is a fundamental species difference in the organization of descending somatosensory pathways. A corticothalamic projection of the AES was also observed. This descending projection appeared to form a shell of labeled cells and fibers around the ventrobasal complex, but unequivocal terminal labeling within the ventrobasal complex could not be demonstrated. Dense terminal labeling was apparent in the posterior group of thalamic nuclei (PO) where thalamocortical afferents to the AES originate.