Winstein C J, Pohl P S
Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles 90033, USA.
Exp Brain Res. 1995;105(1):163-74. doi: 10.1007/BF00242191.
Insight into the functional neural substrates associated with the control of goal-directed purposive movements can be obtained through the study of the performance of individuals with brain damage. The control of rapid reciprocal aiming was investigated by comparing ipsilateral limb performance of subjects with unilateral brain damage to that of controls performing with the same limb. Thirty right-hand-dominant individuals, ten with right hemisphere stroke, ten with left hemisphere stroke, and ten age-matched controls performed unconstrained alternating tapping movements under three conditions of task complexity. The path of the stylus was recorded by video using two-dimensional kinematic techniques. Key kinematic features of the vertical and horizontal components of the trajectories were analyzed using both quantitative and qualitative methods. All subjects with brain damage showed prolonged movement times; however, the locus of the slowing depended on lesion side. Specifically, subjects with left stroke showed deficits in the open-loop component of the movement across all three conditions of task complexity, and a prolonged reversal phase surrounding target impact, particularly in the most complex condition. In contrast, subjects with right stroke showed deficits in the closed-loop phase of the movement prior to target impact, particularly in the most complex condition when visual information was necessary for accuracy. Together, these results suggest that for the control of rapid goal-directed aiming movements, the left hemisphere is dominant for task-relevant aspects of processing associated with the ballistic component and the timing or triggering of sequential movements. In contrast, the right hemisphere is dominant for processing associated with rapid, on-line visual information even when target location is known and direction is certain.
通过对脑损伤个体的行为表现进行研究，可以深入了解与目标导向性有目的运动控制相关的功能性神经基质。通过比较单侧脑损伤受试者患侧肢体的表现与对照组相同肢体的表现，来研究快速交替瞄准的控制情况。30名惯用右手的个体参与了实验，其中10名患有右半球中风，10名患有左半球中风，另外10名是年龄匹配的对照组。他们在三种任务复杂程度条件下进行无约束的交替敲击运动。使用二维运动学技术通过视频记录笔的运动轨迹。运用定量和定性方法分析轨迹垂直和水平分量的关键运动学特征。所有脑损伤受试者的运动时间都延长了；然而，减慢的部位取决于损伤的一侧。具体而言，左半球中风的受试者在所有三种任务复杂程度条件下的运动开环部分都存在缺陷，并且在目标撞击周围的反向阶段延长，尤其是在最复杂的条件下。相比之下，右半球中风的受试者在目标撞击前的运动闭环阶段存在缺陷，尤其是在最复杂的条件下，此时视觉信息对于准确性是必要的。总之，这些结果表明，对于快速目标导向性瞄准运动的控制，左半球在与弹道成分以及连续运动的时间或触发相关的任务相关处理方面占主导地位。相比之下，即使目标位置已知且方向确定，右半球在与快速在线视觉信息相关的处理方面占主导地位。
