Fisk J D, Goodale M A
Department of Psychology, Camp Hill Hospital, Halifax, Nova Scotia, Canada.
Exp Brain Res. 1988;72(2):425-35. doi: 10.1007/BF00250264.
Groups of patients suffering from unilateral damage to the left or right cerebral hemisphere were compared to a group of age-matched normal controls in a visually guided pointing task. Subjects were required to reach quickly and accurately to small visual targets as soon as they appeared on the screen in front of them. All reaches, which were quite unrestricted, were videotaped by rotary-shutter cameras and analyzed by a computer-assisted system which allowed analysis of the kinematic parameters of the movement in three-dimensional space. The groups were compared on the basis of their latency to initiate a reaching movement, the accuracy with which they achieved the target's position, and various measures derived from the instantaneous velocity of the movement. Both patient groups were found to be less accurate than controls and to require more time after the target was illuminated to complete the reach. But while the right-hemisphere group took longer to initiate a reach, the kinematic parameters of the movements they produced did not differ from those of the control group. In contrast, the left-hemisphere group did not differ from the control group in the time required to initiate a reaching movement but did require a greater period of time to execute the reach once it had been initiated. It is suggested that the right hemisphere group were deficient in the speed with which they could determine the spatial position of the target, while the left hemisphere group were deficient in their ability to select an appropriate motor program to achieve the target position and/or to monitor the movement and update the motor program as it was being executed.
在一项视觉引导的指向任务中，将患有左脑或右脑半球单侧损伤的患者组与一组年龄匹配的正常对照组进行了比较。要求受试者在视觉目标出现在他们面前的屏幕上后，尽快快速准确地指向这些小目标。所有动作都是相当自由的，由旋转快门相机录制，并由一个计算机辅助系统进行分析，该系统允许对三维空间中运动的运动学参数进行分析。根据启动伸手动作的潜伏期、到达目标位置的准确性以及从运动的瞬时速度得出的各种测量指标对各组进行比较。发现两个患者组的准确性都低于对照组，并且在目标亮起后需要更多时间才能完成伸手动作。但是，虽然右脑组启动伸手动作花费的时间更长，但他们产生的动作的运动学参数与对照组没有差异。相比之下，左脑组在启动伸手动作所需的时间上与对照组没有差异，但在动作启动后执行伸手动作确实需要更长的时间。有人认为，右脑组在确定目标空间位置的速度方面存在缺陷，而左脑组在选择合适的运动程序以达到目标位置和/或在执行运动时监测运动并更新运动程序的能力方面存在缺陷。
