Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
Curr Biol. 2010 Jan 26;20(2):176-81. doi: 10.1016/j.cub.2009.11.063. Epub 2010 Jan 21.
The cortical visuomotor grasping circuit, comprising the anterior intraparietal area (AIP), ventral premotor (PMv), and primary motor cortex (M1) allows transformation of an object's physical properties into a suitable motor command for grasp [1-9]. However, little is known about how AIP contributes to the processing of grasp-related information conveyed through the cortical grasping circuit. We addressed this by studying the consequences of AIP "virtual lesions" on physiological interactions between PMv and M1 at rest or during preparation to grasp objects with either a precision grip or a whole-hand grasp. We used a conditioning-test transcranial magnetic stimulation (TMS) paradigm to test how PMv-M1 interactions [10-12] were modified by disrupting AIP function with theta-burst TMS (cTBS) [13]. At rest, AIP virtual lesions did not modify PMv-M1 interactions. In contrast, the usual muscle-specific PMv-M1 interactions that appeared during grasp preparation were significantly reduced following AIP cTBS without directly modifying corticospinal excitability. Behaviorally, disruption of AIP was also associated with a relative loss of the grasp-specific pattern of digit muscle activity. These findings suggest that grasp-related and muscle-specific PMv-M1 interactions are driven by information about object properties provided by AIP.
皮质视动抓握回路包括前顶内沟（AIP）、腹侧运动前区（PMv）和初级运动皮层（M1），它将物体的物理属性转换为适合抓握的运动指令[1-9]。然而，关于 AIP 如何参与通过皮质抓握回路传递的与抓握相关的信息处理，我们知之甚少。我们通过研究 AIP“虚拟损伤”对 PMv 和 M1 之间在休息或准备用精确抓握或全手握持物体时的生理相互作用的影响来解决这个问题。我们使用条件-测试经颅磁刺激（TMS）范式来测试通过θ爆发 TMS（cTBS）[13]破坏 AIP 功能如何改变 PMv-M1 相互作用[10-12]。在休息时，AIP 虚拟损伤不会改变 PMv-M1 相互作用。相比之下，在 AIP cTBS 后，在抓握准备期间出现的通常与肌肉特异性相关的 PMv-M1 相互作用明显减少，而不会直接改变皮质脊髓兴奋性。行为上，AIP 的破坏也与数字肌肉活动的抓握特异性模式的相对丧失有关。这些发现表明，与抓握相关的和肌肉特异性的 PMv-M1 相互作用是由 AIP 提供的关于物体属性的信息驱动的。
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