Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712, USA.
Cereb Cortex. 2011 Apr;21(4):865-76. doi: 10.1093/cercor/bhq159. Epub 2010 Aug 25.
The organization of forelimb representation areas of the monkey, cat, and rat motor cortices has been studied in depth, but its characterization in the mouse lags far behind. We used intracortical microstimulation (ICMS) and cytoarchitectonics to characterize the general organization of the C57BL/6 mouse motor cortex, and the forelimb representation in more detail. We found that the forelimb region spans a large area of frontal cortex, bordered primarily by vibrissa, neck, shoulder, and hindlimb representations. It included a large caudal forelimb area, dominated by digit representation, and a small rostral forelimb area, containing elbow and wrist representations. When the entire motor cortex was mapped, the forelimb was found to be the largest movement representation, followed by head and hindlimb representations. The ICMS-defined motor cortex spanned cytoarchitecturally identified lateral agranular cortex (AGl) and also extended into medial agranular cortex. Forelimb and hindlimb representations extended into granular cortex in a region that also had cytoarchitectural characteristics of AGl, consistent with the primary motor-somatosensory overlap zone (OL) characterized in rats. Thus, the mouse motor cortex has homologies with the rat in having 2 forelimb representations and an OL but is distinct in the predominance of digit representations.
猴、猫和鼠大脑运动皮层的前肢代表区的组织已被深入研究，但在小鼠中的特征描述远远落后。我们使用皮层内微刺激（ICMS）和细胞构筑学来描述 C57BL/6 小鼠运动皮层的一般组织，并更详细地描述前肢代表区。我们发现，前肢区域跨越了额叶皮层的大片区域，主要由触须、颈部、肩部和后肢代表区构成。它包括一个以数字代表为主的大型尾侧前肢区，和一个包含肘部和腕部代表区的小型吻侧前肢区。当整个运动皮层被映射时，发现前肢是最大的运动代表区，其次是头部和后肢代表区。ICMS 定义的运动皮层跨越了细胞构筑学上确定的外侧颗粒层（AGl），并延伸到内侧颗粒层。前肢和后肢代表区延伸到颗粒层，该区域也具有 AGl 的细胞构筑学特征，与在大鼠中特征化的主要运动感觉重叠区（OL）一致。因此，小鼠运动皮层与大鼠具有 2 个前肢代表区和一个 OL 具有同源性，但在以数字代表为主方面存在差异。
