Lozsádi D A
Department of Human Anatomy, University of Oxford, England.
J Comp Neurol. 1995 Jul 24;358(2):233-46. doi: 10.1002/cne.903580206.
The thalamic reticular nucleus (TRN) receives topographically organized input from specific sensory nuclei such as the lateral geniculate nucleus. The present study shows this in the rat. However, the pattern of thalamic connections to the limbic reticular sector is unknown. Injecting biocytin into the ventral parts of anteroventral and anteromedial nuclei labeled neurons and axons in the rostral TRN. Filled axon collaterals and their terminals occupied a rectangular sheet in a plane close to the horizontal, and were confined to the inner zone (the medial portion) of the limbic TRN. Retrogradely filled cells were in the middle of the rostral pole in the same horizontal plane, receiving synapses from surrounding labeled boutons. In electron micrographs, thalamic terminals were found to contain round, densely packed synaptic vesicles and formed asymmetrical synapses onto reticular somata and dendritic profiles. Displacing the injection site along the dorso-ventral and rostro-caudal axis in the anterior nuclei produced corresponding shifts of antero- and retrograde labeling within the inner reticular zone. Projections from the dorsal portions of the anterior nuclei did not follow this pattern. Axons from the anterodorsal nucleus occupied the rostralmost tip of both inner and outer zones of the dorsal limbic sector. In accordance with earlier reports, the limbic sector was found to represent several dorsal thalamic nuclei parallel to each other medio-laterally. A topography is described for the limbic reticulo-thalamic connections, suggesting that the rostral TRN is able to influence circumscribed areas of the limbic thalamus.
丘脑网状核（TRN）从特定的感觉核团，如外侧膝状体核，接收拓扑组织化的输入。本研究在大鼠中证实了这一点。然而，丘脑与边缘网状区的连接模式尚不清楚。将生物胞素注入腹前核和腹内侧核的腹侧部分，标记了嘴侧TRN中的神经元和轴突。充满的轴突侧支及其终末在接近水平的平面内占据一个矩形薄片，并局限于边缘TRN的内侧区域（内侧部分）。逆行标记的细胞位于同一水平面嘴侧极的中部，接受来自周围标记终扣的突触。在电子显微镜照片中，发现丘脑终末含有圆形、紧密堆积的突触小泡，并在网状体细胞和树突轮廓上形成不对称突触。在前核中沿背腹轴和嘴尾轴移动注射部位，在内侧网状区内产生相应的顺行和逆行标记移位。前核背侧部分的投射不遵循这种模式。来自前背核的轴突占据背侧边缘区内侧和外侧区的最嘴端。与早期报告一致，发现边缘区代表几个彼此平行的背侧丘脑核，在内外侧方向排列。描述了边缘网状-丘脑连接的一种拓扑结构，表明嘴侧TRN能够影响边缘丘脑的特定区域。
