Properties of Eye-Head Co-ordination during Visually Guided Gaze Shifts in Humans

当引入间隙任务（目标在注视点FP消失后200 ms出现）时，视觉引导扫视（SRT）的延迟缩短了100 ms。为什么最短的反应隐藏在日常生活中是本项目的主题。在第一个实验中，测量SRT，同时在外围目标出现之前FP的颜色从红色变为绿色（RG范例），以理解FP偏移在扫视启动中的作用。RG范式相对于常规任务更快地完成SRT。在第二个实验中，眼睛和头部运动系统之间的耦合在凝视转移进行了检查。当反射（目标导向）和自愿（反目标导向）的任务交错，受试者在最初的头部运动方向的错误，在某些情况下，单独发散不正确的头部和正确的眼球运动。研究结果与普遍认为的在视线转移过程中头和眼之间存在紧密耦合的观点形成对比，并表明两者在人类中是独立控制的。这两个运动系统之间的耦合比较是更灵活的顺序，人类，猴子和猫。最后的实验研究是否有任何向下扫视在较低的视野显示均匀缓慢的起始时间，因为向下扫视相比，向上扫视的缺点已被解释从生态学的观点。单纯向下眼跳的平均潜伏期显著长于单纯水平眼跳。然而，水平或向下成分的斜眼跳的潜伏期是一样快的纯水平眼跳。结果表明，在下视野范围内存在明显的SRT偏差。这些结果揭示了人类视线转移的特性。

Latencies of visually guided saccades (SRTs) are shortened by 100ms when a gap task (target appears 200ms after disappearance of the fixation point FP) is introduced. Why the shortest reaction is hidden in everyday life was the main theme of the present project. In the first experiment, SRTs were measured while a color of the FP was changed from red to green prior to the peripheral target appearance (RG paradigm), to understand the role of the FP offset in saccade initiation. The RG paradigm fastened SRTs relative to the conventional tasks. In the second experiment, coupling between eye and head motor systems during gaze shifts were examined. When the reflexive (target-directed) and voluntary (anti-target-directed) tasks were interleaved, subjects made directional errors in the initial head movements alone in some occasions; diverged incorrect head and correct eye movements. The results are contrast to the commonly held view that there is a tight coupling between head and eye during gaze shifts, and suggest that both are controlled independently in humans. Comparison of the coupling between both motor systems is more flexible in the order of human, monkey and cat. The final experiment examined whether any downward saccades across the lower visual field show uniformly slow onset time, because a disadvantage for downward saccade as compared with upward saccade has been explained from ecological viewpoints. The mean latency of purely downward saccades was significantly longer than that of purely horizontal saccades. However, latency of horizontal or downward components of oblique saccades was as fast as the purely horizontal saccades. The result indicates that there exists an apparent SRT bias within the lower visual field. The properties of human gaze shifts came to light from these results.