THE PRIMATE MEDIODORSAL (MD) NUCLEUS AND ITS PROJECTION TO THE FRONTAL-LOBE
THE PRIMATE MEDIODORSAL (MD) NUCLEUS AND ITS PROJECTION TO THE FRONTAL-LOBE
复制标题
DOI：
10.1002/cne.902420406
复制
发表时间：
1985-12-22
影响因子：
2.5
通讯作者：
PORRINO, LJ
中科院分区：
文献类型：
--
作者：
GOLDMANRAKIC, PS;PORRINO, LJ
通过将逆行标记注射到位于大脑前三分之一的九个细胞结构区之一（沃克区 6、8A、9、10、11、12、13、46 和布罗德曼区 4）之一，对恒河猴丘脑中背核 (MD) 的额叶投射进行了检查。发现注射的前额叶、前运动或运动皮层的每个区域都从 MD 内特定细分的细胞簇接收地形上独特的丘脑输入。所有检查的前额叶区域还接收来自其他丘脑核的按地形组织的输入，其中最突出的是腹侧前核（VA）和内侧丘脑核。相反，与之前的发现一致，MD 投射到前额皮质传统边界之外的额叶区域，例如前扣带皮层和辅助运动皮层。在通过 VA、MD 和枕丘的冠状切片中显示的丘脑皮质神经元的地形是圆周的。例如，在 MD 的内侧部分，丘脑皮层神经元从背侧位置移动到腹侧位置，以便沿着叶的腹侧表面从内侧到外侧的皮质目标；对于位于半球凸面外侧到内侧的皮质区域，外侧 MD 中的神经元从腹侧移动到背侧位置。地形特异性的综合证据得到了实验的进一步支持，在这些实验中，在三种情况下，不同的荧光染料被放置在额叶的多个区域中。结果表明，即使有的话，丘脑神经元也很少投射到多个皮层区域。 MD神经元广泛的皮质目标以及前额叶区域的多个丘脑输入的证据支持对前额皮质作为MD投射的唯一皮质接受者的经典方法学定义的修订。相反，前额叶皮层是由与丘脑的多种特定关系定义的。
The frontal lobe projectons of the mediodorsal (MD) nucleus of the thalamus were examined in rhesus monkey by transport of retrograde markers injected into one of nine cytoarchitectonic regions (Walker''s areas 6, 8A, 9, 10, 11, 12, 13, 46, and Brodmann''s area 4) located in the rostral third of the cerebrum. Each area of prefrontal, premotor, or motor cortex injected was found to receive a topographically unique thalamic input from clusters of cells in specific subdivisions within MD. All of the prefrontal areas examined also receive topographically organized inputs from other thalamic nuclei including, most prominently, the ventral anterior (VA) and medial pulvinar nuclei. Conversely, and in agreement with previous findings, MD projects to areas of the frontal lobe beyond the traditional borders of prefrontal cortex, such as the anterior cingulate and supplementary motor cortex. The topography of thalamocortical neurons revealed in coronal sections through VA, MD, and pulvinar is circumferential. In the medial part of MD, for example, thalamocortical neurons shift from a dorsal to a ventral position for cortical targets lying medial to lateral along the ventral surface of the lobe; neurons in the lateral MD move from a ventral to a dorsal position, for cortical areas situated lateral to medial on the convexity of the hemisphere. The aggregate evidence for topographic specificity is supported further by experiments in which different fluorescent dyes were placed in mutliple areas of the frontal lobe in each of three cases. The results show that very few, if any, thalamic neurons project to more than one area of cortex. The widespread cortical targets of MD neurons together with evidence for multiple thalamic inputs to prefrontal areas support a revision of the classical hodological definition of prefrontal cortex as the exclusive cortical recipient of MD projections. Rather, the prefrontal cortex is defined by multiple specific relationships with the thalamus.