Soechting John F, Flanders Martha
Department of Neuroscience, University of Minnesota, 6-145 Jackson Hall, 321 Church St. SE, Minneapolis, MN 55455, USA.
J Neurophysiol. 2008 Jun;99(6):2956-67. doi: 10.1152/jn.90308.2008. Epub 2008 Apr 24.
A frequent goal of hand movement is to touch a moving target or to make contact with a stationary object that is in motion relative to the moving head and body. This process requires a prediction of the target's motion, since the initial direction of the hand movement anticipates target motion. This experiment was designed to define the visual motion parameters that are incorporated in this prediction of target motion. On seeing a go signal (a change in target color), human subjects slid the right index finger along a touch-sensitive computer monitor to intercept a target moving along an unseen circular or oval path. The analysis focused on the initial direction of the interception movement, which was found to be influenced by the time required to intercept the target and the target's distance from the finger's starting location. Initial direction also depended on the curvature of the target's trajectory in a manner that suggested that this parameter was underestimated during the process of extrapolation. The pattern of smooth pursuit eye movements suggests that the extrapolation of visual target motion was based on local motion cues around the time of the onset of hand movement, rather than on a cognitive synthesis of the target's pattern of motion.
手部运动的一个常见目标是触摸移动的目标，或与相对于移动的头部和身体处于运动状态的静止物体接触。这个过程需要对目标的运动进行预测，因为手部运动的初始方向要预判目标的运动。本实验旨在确定纳入目标运动预测的视觉运动参数。看到开始信号（目标颜色变化）后，人类受试者沿着触摸感应电脑显示器滑动右手食指，以拦截沿不可见圆形或椭圆形路径移动的目标。分析集中在拦截动作的初始方向，发现其受拦截目标所需时间以及目标与手指起始位置的距离影响。初始方向还取决于目标轨迹的曲率，这表明在推断过程中该参数被低估了。平稳跟踪眼球运动模式表明，视觉目标运动的推断基于手部运动开始时周围的局部运动线索，而非目标运动模式的认知综合。
