Muscle representation in the macaque motor cortex: An anatomical perspective
Muscle representation in the macaque motor cortex: An anatomical perspective
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DOI：
10.1073/pnas.0602933103
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发表时间：
2006-05-23
影响因子：
11.1
通讯作者：
Strick, Peter L.
中科院分区：
文献类型：
--
作者：
Rathelot, Jean-Alban;Strick, Peter L.
直接影响肌肉运动神经元的神经元如何分布在初级运动皮层（M1）？为了回答这个经典的问题，我们使用了狂犬病病毒从猕猴的单个肌肉的逆行transneuronal运输。这使我们能够定义皮质运动神经元（CM）细胞与注射肌肉的运动神经元进行单突触连接。我们研究了CM细胞的分布，项目的运动神经元的三个拇指和手指肌肉。我们发现，这些手指肌肉的CM细胞仅限于尾侧部分的M1，这是埋在中央沟。在M1的这个区域内，一个肌肉的CM细胞显示出非常广泛的分布，并填充了手臂区域的整个内外侧范围。事实上，手指肌肉的CM细胞位于M1的区域中，已知这些区域包含肩部代表。不同肌肉的CM细胞所占据的皮质区域广泛重叠。因此，我们没有发现证据的一个单一的肌肉在M1的局灶性代表。相反，CM细胞的不同群体之间的重叠和混合可能是创造各种肌肉协同作用的神经基质。我们发现了另外两个令人惊讶的结果。首先，15-16%的CM细胞来自3a区，初级sornatosensory皮层的一个区域。第二，CM细胞的大小范围包括“快”和“慢”锥体束神经元。这些观察结果可能会导致对CM系统功能的看法发生巨大变化。
How are the neurons that directly influence the motoneurons of a muscle distributed in the primary motor cortex (M1)? To answer this classical question we used retrograde transneuronal transport of rabies virus from single muscles of macaques. This enabled us to define cortico-motoneuronal (CM) cells that make monosynaptic connections with the motoneurons of the injected muscle. We examined the distribution of CM cells that project to motoneurons of three thumb and finger muscles. We found that the CM cells for these digit muscles are restricted to the caudal portion of M1, which is buried in the central sulcus. Within this region of M1, CM cells for one muscle display a remarkably widespread distribution and fill the entire mediolateral extent of the arm area. In fact, CM cells for digit muscles are found in regions of M1 that are known to contain the shoulder representation. The cortical territories occupied by CM cells for different muscles overlap extensively. Thus, we found no evidence for a focal representation of single muscles in M1. Instead, the overlap and intermingling among the different populations of CM cells may be the neural substrate to create a wide variety of muscle synergies. We found two additional surprising results. First, 15-16% of the CM cells originate from area 3a, a region of primary sornatosensory cortex. Second, the size range of CM cells includes both "fast" and "slow" pyramidal tract neurons. These observations are likely to lead to dramatic changes in views about the function of the CM system.