THALAMIC PROJECTIONS TO AREA-3A, AREA-3B, AND AREA-4 IN THE SENSORIMOTOR CORTEX OF THE MATURE AND INFANT MACAQUE MONKEY
THALAMIC PROJECTIONS TO AREA-3A, AREA-3B, AND AREA-4 IN THE SENSORIMOTOR CORTEX OF THE MATURE AND INFANT MACAQUE MONKEY
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DOI：
10.1002/cne.903350204
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发表时间：
1993-09-08
影响因子：
2.5
通讯作者：
DARIANSMITH, I
中科院分区：
文献类型：
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作者：
DARIANSMITH, C;DARIANSMITH, I
猕猴的 3a 区位于中央沟的底部，将运动皮质区 4 和体感皮质区 3b 分开。区域 4 和区域 3b 的已知连接有很大不同，它们接收、处理和传输到中枢神经系统其他部分的信息也有很大不同。在该分析中，通过使用逆行传输的荧光染料（坚牢蓝、二脒基黄、罗丹明和绿色乳胶微球）作为神经元标记，检查和比较了丘脑对这三个皮质区域的投射。对每只猴子 2-3 个皮质位点的投影进行一致标记，可以直接比较投射到区域 3a、3b 和 4 以及这些皮质区域之间的边界区域的不同神经元群的丘脑空间内的体细胞分布。丘脑神经元的体细胞分布严格地投射到皮质区域 3a（手代表区域）内的一个小限制区域（直径 = 0.5-1.0 mm），填充了一个穿过细胞结构定义的丘脑核 VPLc 背侧一半的“区域”（缩写如 Olszewski [1952] 猕猴的丘脑）。巴塞尔：卡尔格）。这个细长的、相当圆柱形的区域向后延伸到前枕核，但不向前延伸到 VPLo。定义投射到皮质区域 3b 小区域的神经元体分布的丘脑区域的轴尾范围是相似的，但通常延伸到 VPLc 的腹侧部分，填充内侧凹凸层流空间。两个这样的区域分别投射到区域 3a 和 3b 的相邻区域，重叠并共享丘脑空间，但不共享丘脑神经元。与 3a 和 3b 丘脑区域相比，投射到附近运动皮层（区域 4）的限制区域的丘脑神经元的体体分布并没有渗透到 VPLc，而是填充了从头侧 VLo、VLm、VPLo 延伸到尾侧和背侧 VLc、LP 和 Pul.o 的中侧扁平区域。这些地区都围绕着 VPLc。所有三个皮质区域 4、3a 和 3b) 也接收来自层内 Cn.Md 中独特细胞簇的输入。据推测，丘脑区域结合起来，包围着那些投射到区域 3a、3b 和 4（以及区域 1 和 2）中的感觉运动手表征的神经元体，这些神经元体在执行手动任务期间会协同工作，构成了从 VLo 喙部延伸到 Pul.o 尾部的层状空间。 Pul.o 神经元群体如何与同一丘脑区域内投射到局部皮质区的更多喙侧群体相关仍然不确定。在位于内侧的区域内，Pul.o 中神经元群的分布在空间上是连续的，更多的丘脑嘴部细胞投射到相同的局部皮层，但在外侧丘脑区域中，这两个神经元群通常在空间上不连续。在新生猕猴中，4、3a 和 3b 区域的领土投影也出现了有序变化。然而，丘脑核投射比成熟动物更广泛。除了 VPLc 输入之外，3a 区丘脑输入的三分之一现在来自 VLo、VPLo 和 VLm。区域 4 也有来自 VPLc 的重要输入，这是在成熟猕猴中未观察到的输入。 (C) 1993 Wiley-Liss, Inc.
Area 3a in the macaque monkey, located in the fundus of the central sulcus, separates motor and somatosensory cortical areas 4 and 3b. The known connections of areas 4 and 3b differ substantially, as does the information which they receive, process, and transfer to other parts of the central nervous system. In this analysis the thalamic projections to each of these three cortical fields were examined and compared by using retrogradely transported fluorescent dyes (Fast Blue, Diamidino Yellow, Rhodamine and Green latex microspheres) as neuron labels. Coincident labeling of projections to 2-3 cortical sites in each monkey allowed the direct comparison of the soma distributions within the thalamic space of the different neuron populations projecting to areas 3a, 3b, and 4, as well as to boundary zones between these cortical fields. The soma distribution of thalamic neurons projecting to a small circumscribed zone (diameter = 0.5-1.0 mm) strictly within cortical area 3a (in region of hand representation) filled out a ''territory'' traversing the dorsal half of the cytoarchitectonically defined thalamic nucleus, VPLc (abbreviations as in Olszewski [1952] The Thalamus of the Macaca mulatta. Basel: Karger). This elongate, rather cylindrical, territory extended caudally into the anterior pulvinar nucleus, but not forward into VPLo. The rostrocaudal extent of the thalamic territory defining the soma distribution of neurons projecting to small zones of cortical area 3b was similar, but typically extended into the ventral part of VPLc, filling out a medially concavo-convex laminar space. Two such territories projecting to adjacent zones of areas 3a and 3b, respectively, overlapped and shared thalamic space, but not thalamic neurons. Contrasting with the 3a and 3b thalamic territories, the soma distribution of thalamic neurons projecting to a circumscribed zone in the nearby motor cortex (area 4) did not penetrate into VPLc, but instead filled out a mediolaterally flattened territory extending from rostral VLo, VLm, VPLo to caudal and dorsal VLc, LP, and Pul.o. These territories skirted around VPLc. All three cortical areas 4, 3a, and 3b) also received input from distinctive clusters of cells in the intralaminar Cn.Md. It is inferred that, in combination, the thalamic territories enveloping those neuron somas projecting to, say, the sensorimotor hand representation in areas 3a, 3b, and 4 (and also areas 1 and 2), which would be coactive during the execution of a manual task, constituted a lamellar space extending from VLo rostrally to Pul.o caudally. How Pul.o neuron populations relate to the more rostral populations within the same thalamic territory projecting to a localized cortical zone remains uncertain. Within the medially located territories the distribution of the neuron population in Pul.o was spatially continuous with the more rostral thalamic cells projecting to the same localized cortex, but in lateral thalamic territories these 2 populations were usually spatially discontinuous. In the newborn macaque an orderly change in the territorial projections to localized zones in areas 4, 3a, and 3b was also demonstable. However, thalamic nuclear projections were more expansive than in the mature animal. As well as the VPLc input, a third of the thalamic input to area 3a was now from VLo, VPLo, and VLm. Area 4 also had a significant input from VPLc, an input not observed in the mature macaque. (C) 1993 Wiley-Liss, Inc.