Animal brains contain behaviorally committed representations of the surrounding world, which integrate sensory and motor information. In primates, sensorimotor mechanisms reside in part in the premotor cortex (PM), where sensorimotor neurons are topographically clustered according to functional specialization. Detailed functional cartography of the human PM is still under investigation. We explored the topographic distribution of spatially dependent sensorimotor functions in healthy volunteers performing left or right, hand or foot, responses to visual cues presented in the left or right hemispace, thus combining independently stimulus side, effector side, and effector type. Event-related transcranial magnetic stimulation was applied to single spots of a dense grid of 10 points on the participants' left hemiscalp, covering the whole PM. Results showed: (1) spatially segregated hand and foot representations, (2) focal representations of contralateral cues and movements in the dorsal PM, and (3) distributed representations of ipsilateral cues and movements in the ventral and dorso-medial PM. The present novel causal information indicates that (1) the human PM is somatotopically organized and (2) the left PM contains sensory-motor representations of both hemispaces and of both hemibodies, but the hemispace and hemibody contralateral to the PM are mapped on a distinct, nonoverlapping cortical region compared to the ipsilateral ones.

中文翻译：

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两个不同的系统代表人类前运动皮层中的对侧和同侧感觉运动过程：密集的 TMS 映射研究。

动物大脑包含对周围世界的行为承诺表征，这些表征整合了感官和运动信息。在灵长类动物中，感觉运动机制部分存在于运动前皮层 (PM)，其中感觉运动神经元根据功能特化在地形上聚集。人类 PM 的详细功能制图仍在调查中。我们探索了健康志愿者的空间依赖性感觉运动功能的地形分布，这些志愿者对左半空间或右半空间中呈现的视觉线索做出反应，从而独立地结合了刺激侧、效应侧和效应器类型。将事件相关的经颅磁刺激应用于参与者左半脑上 10 个点的密集网格的单个点，覆盖整个 PM。结果显示：(1) 空间分离的手和脚表示，(2) 背侧 PM 中对侧线索和运动的焦点表示，以及 (3) 腹侧和背内侧 PM 中同侧线索和运动的分布式表示。目前的新因果信息表明 (1) 人类 PM 是躯体组织的，(2) 左侧 PM 包含两个半空间和两个半体的感觉运动表征，但半空间和 PM 对侧的半体被映射到不同的，与同侧皮层区域相比，不重叠的皮层区域。