Department of Biomedical and Neuromotor Sciences, University of Bologna, Piazza Porta San Donato 2, 40126 Bologna, Italy.
Neurosci Biobehav Rev. 2022 Oct;141:104823. doi: 10.1016/j.neubiorev.2022.104823. Epub 2022 Aug 9.
In the macaque, the posterior parietal area V6A is involved in the control of all phases of reach-to-grasp actions: the transport phase, given that reaching neurons are sensitive to the direction and amplitude of arm movement, and the grasping phase, since reaching neurons are also sensitive to wrist orientation and hand shaping. Reaching and grasping activity are corollary discharges which, together with the somatosensory and visual signals related to the same movement, allow V6A to act as a state estimator that signals discrepancies during the motor act in order to maintain consistency between the ongoing movement and the desired one. Area V6A is also able to encode the target of an action because of gaze-dependent visual neurons and real-position cells. Here, we advance the hypothesis that V6A also uses the spotlight of attention to guide goal-directed movements of the hand, and hosts a priority map that is specific for the guidance of reaching arm movement, combining bottom-up inputs such as visual responses with top-down signals such as reaching plans.
在后顶叶区域 V6A 中，猕猴控制着抓握动作的所有阶段：在运动阶段，因为到达神经元对手臂运动的方向和幅度敏感，以及在抓握阶段，因为到达神经元对手腕方向和手形也敏感。到达和抓握活动是伴随运动，与同一运动相关的体感和视觉信号一起，使 V6A 能够作为状态估计器，在运动过程中发出差异信号，以保持正在进行的运动和期望运动之间的一致性。由于依赖于注视的视觉神经元和实际位置细胞，V6A 也能够对动作的目标进行编码。在这里，我们提出假设，即 V6A 还使用注意力的聚光灯来引导手的目标导向运动，并承载一个特定的优先级映射，用于引导手臂运动，将自上而下的信号（如到达计划）与自下而上的输入（如视觉反应）相结合。
