Schoppik David, Lisberger Stephen G
Howard Hughes Medical Institute, Neuroscience Graduate Program, W. M. Keck Foundation Center for Integrative Neuroscience, and Department of Physiology, University of California, San Francisco, California 94143, USA.
J Neurosci. 2006 Jul 19;26(29):7607-18. doi: 10.1523/JNEUROSCI.1719-06.2006.
Saccades modulate the relationship between visual motion and smooth eye movement. Before a saccade, pursuit eye movements reflect a vector average of motion across the visual field. After a saccade, pursuit primarily reflects the motion of the target closest to the endpoint of the saccade. We tested the hypothesis that the saccade produces a spatial weighting of motion around the endpoint of the saccade. Using a moving pursuit stimulus that stepped to a new spatial location just before a targeting saccade, we controlled the distance between the endpoint of the saccade and the position of the moving target. We demonstrate that the smooth eye velocity following the targeting saccade weights the presaccadic visual motion inputs by the distance from their location in space to the endpoint of the saccade, defining the extent of a spatiotemporal filter for driving the eyes. The center of the filter is located at the endpoint of the saccade in space, not at the position of the fovea. The filter is stable in the face of a distracter target, is present for saccades to stationary and moving targets, and affects both the speed and direction of the postsaccadic eye movement. The spatial filter can explain the target-selecting gain change in postsaccadic pursuit, and has intriguing parallels to the process by which perceptual decisions about a restricted region of space are enhanced by attention. The effect of the spatial saccade plan on the pursuit response to a given retinal motion describes the dynamics of a coordinate transformation.
扫视调节视觉运动与平稳眼球运动之间的关系。在扫视之前,追踪眼球运动反映了整个视野中运动的矢量平均值。在扫视之后,追踪主要反映最接近扫视终点的目标的运动。我们测试了这样一个假设,即扫视会在扫视终点周围产生运动的空间加权。通过使用一种在目标扫视之前移动到新空间位置的追踪刺激,我们控制了扫视终点与移动目标位置之间的距离。我们证明,目标扫视后的平稳眼球速度根据其在空间中的位置到扫视终点的距离对扫视前的视觉运动输入进行加权,从而定义了驱动眼球的时空滤波器的范围。滤波器的中心位于空间中的扫视终点,而不是中央凹的位置。面对干扰目标时,该滤波器是稳定的,在扫视静止和移动目标时均存在,并影响扫视后眼球运动的速度和方向。空间滤波器可以解释扫视后追踪中目标选择增益的变化,并且与通过注意力增强对受限空间区域的感知决策的过程有着有趣的相似之处。空间扫视计划对给定视网膜运动的追踪反应的影响描述了坐标变换的动态过程。