Li W X, Matin L
Department of Psychology, Columbia University, New York, NY 10027.
Vision Res. 1990;30(6):945-55. doi: 10.1016/0042-6989(90)90060-x.
The threshold for detection of stimulus displacement, which is normally raised in the presence of voluntary saccades relative to its value during steady fixation ("saccadic suppression of displacement"), decreases from 50x to 25x its value during steady fixation when the duration of the second display is experimentally increased from 33 to 461 msec; further increase of the duration of the second display has no additional effect. It might be expected that this improvement in sensitivity to displacement is a consequence of the elimination from perception of the visible smear corresponding to the saccadic stimulus by the action of metacontrast from the postsaccadic stimulus. That this is not so is shown by the fact that the improvement in displacement sensitivity with increased postsaccadic exposure duration is unaffected by experimental elimination of the retinal stimulus normally present during the saccade, even under conditions for which the saccadic stimulus is normally visible and appears smeared. The results demonstrate that the basis for saccadic suppression of displacement lies in the transient saccade-related modification of extraretinal eye position information.
刺激位移的检测阈值在存在随意性扫视时相对于其在稳定注视期间的值通常会升高（“扫视对位移的抑制”），当第二个显示的持续时间从33毫秒实验性地增加到461毫秒时，该阈值从稳定注视期间的值的50倍降至25倍；第二个显示持续时间的进一步增加没有额外影响。可以预期，对位移敏感性的这种改善是由于扫视后刺激的元对比作用消除了与扫视刺激相对应的可见模糊在感知中的影响。事实表明并非如此，因为即使在扫视刺激通常可见且看起来模糊的条件下，随着扫视后暴露持续时间增加，位移敏感性的改善不受实验性消除扫视期间通常存在的视网膜刺激的影响。结果表明，扫视对位移的抑制的基础在于视网膜外眼位置信息与扫视相关的瞬时变化。
