Release of fixation for pursuit and saccades in humans: Evidence for shared inputs acting on different neural substrates
Release of fixation for pursuit and saccades in humans: Evidence for shared inputs acting on different neural substrates
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DOI：
10.1152/jn.1996.76.5.2822
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发表时间：
1996-11-01
影响因子：
2.5
通讯作者：
Miles, FA
中科院分区：
文献类型：
--
作者：
Krauzlis, RJ;Miles, FA
1. 在三名人类受试者中，我们测量了在固定的中心目标消失后对偏心目标进行追踪和扫视的眼球运动的潜伏期。在一组实验中，我们改变了中心目标消失和偏心目标出现之间的时间间隔（“间隙持续时间”）。在第二组实验中，我们改变了第二个目标出现的偏心率。2．改变间隙持续时间会导致追踪和眼跳的延迟发生类似的变化。短至 30 毫秒的间隙可显着降低延迟；逐渐变长的间隙会产生更短的延迟，间隙达到最小值 150-200 毫秒。在所使用的间隙持续时间范围内，追踪和扫视的延迟表现出与间隙持续时间相同的依赖性。3．改变第二个目标的偏心率会对追踪和扫视的延迟产生不同的影响。当第二个目标的偏心率从 4 度降低到 0.5 度时，扫视延迟会增加，而追踪延迟并没有一致改变。尽管追踪和扫视之间对视网膜偏心率的依赖性存在差异，但在注视点消失和第二个目标出现之间施加 200 毫秒的间隙仍然可以减少两者的延迟。4。我们的结果与这样的观点是一致的，即释放注视追逐和眼跳的机制具有共享的输入，但神经基质不同。对间隙持续时间的共同依赖性可能表明单个准备输入协调沐浴类型的运动。对视网膜偏心率的不同依赖性表明，触发两种类型运动开始的运动前回路的空间组织存在差异。
1. In three human subjects, we measured the latency of pursuit and saccadic eye movements made to an eccentric target after a fixated central target was extinguished. In one set of experiments, we varied the time interval between the extinction of the central target and the appearance of the eccentric target (''gap duration''). In a second set of experiments, we varied the eccentricity at which the second target appeared.2. Varying the gap duration produced similar changes in the latencies of pursuit and saccades. Gaps as short as 30 ms caused significant decreases in latency; progressively longer gaps produced shorter latencies, reaching a minimum for gaps of 150-200 ms. Over the range of gap durations used, the latencies of pursuit and saccades displayed the same dependence on gap duration.3. Varying the eccentricity of the second target produced different effects on the latencies of pursuit and saccades. Saccade latencies increased when the eccentricity of the second target was decreased from 4 degrees to 0.5 degrees, whereas pursuit latencies were not consistently altered. Despite these differences in the dependence on retinal eccentricity between pursuit and saccades, imposing a 200-ms gap between the extinction of the fixation point and appearance of the second target still reduced the latency of both.4. Our results are consistent with the idea that the mechanisms underlying the release of fixation fur pursuit and saccades have shared inputs but a different neural substrate. The common dependence on gap duration may indicate that a single preparatory input coordinates bath types of movements. The different dependence on retinal eccentricity indicates that there are differences in the spatial organization of the premotor circuits that trigger the onset of the two types of movements.