Beke Clarissa, Flindall Jason W, Gonzalez Claudia L R
The Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge, 4401 University Dr W, Lethbridge, AB, T1K 6T5, Canada.
Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, V6T 1Z4, Canada.
Exp Brain Res. 2018 Jun;236(6):1621-1630. doi: 10.1007/s00221-018-5242-2. Epub 2018 Mar 27.
Studies have suggested a left-hemisphere specialization for visually guided grasp-to-eat actions by way of task-dependent kinematic asymmetries (i.e., smaller maximum grip apertures for right-handed grasp-to-eat movements than for right-handed grasp-to-place movements or left-handed movements of either type). It is unknown, however, whether this left-hemisphere/right-hand kinematic advantage is reliant on the dorsal "vision-for-action" visual stream. The present study investigates the kinematic differences between grasp-to-eat and grasp-to place actions performance during closed-loop (i.e., dorsally mediated) and open-loop delay (i.e., ventrally mediated) conditions. Twenty-one right-handed adult participants were asked to reach to grasp small food items to (1) eat them, or (2) place them in a container below the mouth. Grasps were performed in both closed-loop and open-loop delay conditions, in separate sessions. We show that participants displayed the right-hand grasp-to-eat kinematic advantage in the closed-loop condition, but not in the open-loop delay condition. As no task-dependent kinematic differences were found in ventrally mediated grasps, we posit that the left-hemisphere/right-hand advantage is dependent on dorsal stream processing.
研究表明，通过任务依赖的运动不对称性（即右手抓握取食动作的最大抓握孔径小于右手抓握放置动作或任何一种类型的左手动作），左半球在视觉引导的抓握取食动作上具有特异性。然而，尚不清楚这种左半球/右手运动优势是否依赖于背侧“行动视觉”视觉流。本研究调查了在闭环（即背侧介导）和开环延迟（即腹侧介导）条件下，抓握取食和抓握放置动作表现之间的运动差异。21名右利手成年参与者被要求伸手抓取小食物（1）吃掉它们，或（2）将它们放入嘴下方的容器中。抓握动作在闭环和开环延迟条件下分别进行。我们发现，参与者在闭环条件下表现出右手抓握取食的运动优势，但在开环延迟条件下则没有。由于在腹侧介导的抓握中未发现任务依赖的运动差异，我们认为左半球/右手优势依赖于背侧流处理。
