Hand Orientation during Reach-to-Grasp Movements Modulates Neuronal Activity in the Medial Posterior Parietal Area V6A
Hand Orientation during Reach-to-Grasp Movements Modulates Neuronal Activity in the Medial Posterior Parietal Area V6A
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DOI：
10.1523/jneurosci.4998-08.2009
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发表时间：
2009-02-11
影响因子：
5.3
通讯作者：
Galletti, Claudio
中科院分区：
文献类型：
--
作者：
Fattori, Patrizia;Breveglieri, Rossella;Galletti, Claudio
伸手抓握动作包括前肢动作的几个组成部分，这些动作需要将手指向要抓住的物体，并根据物体的轴和形状来定位和预先塑造手的形状。V6A区代表背内侧额顶神经回路的一个节点，到目前为止，它只涉及将手臂指向不同的空间位置。目前的结果证实了这一发现，并首次证明，在伸展到抓握的过程中，V6A神经元也受到手的方向的调制。在目前的工作中，要抓住的对象是一个可以有不同方向的手柄。伸手抓住的动作是在完全黑暗的情况下进行的，同时凝视着一个小的凝视点。大多数受测细胞(76/142；54%)对手柄的方向敏感。神经元可以在准备或执行伸手抓住动作的过程中进行调节。最具代表性的细胞是那些在准备阶段和运动阶段都受到手部方向调制的细胞。这些数据表明，伸手和抓握是由同一组神经元处理的，这提供了证据，表明伸手和抓握的协调发生得比之前认为的要早得多，即在顶枕叶皮质。本文报道的数据与猴和人的顶后内侧皮质损伤的结果一致，也与最近人类的成像数据一致，所有这些数据都表明顶额内侧回路控制到达和抓住的功能耦合。
Reach-to-grasp actions involve several components of forelimb movements needed to direct the hand toward the object to be grasped, and to orient and preshape the hand according to the object axis and shape. Area V6A, which represents a node of the dorsomedial frontoparietal circuits, has so far been implicated only in directing the arm toward different spatial locations. The present results confirm this finding and demonstrate, for the first time, that during reach-to-grasp, V6A neurons are also modulated by the orientation of the hand. In the present work the object to be grasped was a handle that could have different orientations. Reach-to-grasp movements were executed in complete darkness while gazing at a small fixation point. The majority of the tested cells (76/142; 54%) turned out to be sensitive to the orientation of the handle. Neurons could be modulated during preparation or execution of reach-to-grasp movements. The most represented cells were those modulated by hand orientation both during preparatory and movement periods. These data show that reaching and grasping are processed by the same population of neurons, providing evidence that the coordination of reaching and grasping takes place much earlier than previously thought, i.e., in the parieto-occipital cortex. The data here reported are in agreement with results of lesions to the medial posterior parietal cortex in both monkeys and humans, and with recent imaging data in humans, all of them indicating a functional coupling in the control of reaching and grasping by the medial parietofrontal circuit.