TEMPORAL PROPERTIES OF VISUAL-MOTION SIGNALS FOR THE INITIATION OF SMOOTH-PURSUIT EYE-MOVEMENTS IN MONKEYS
TEMPORAL PROPERTIES OF VISUAL-MOTION SIGNALS FOR THE INITIATION OF SMOOTH-PURSUIT EYE-MOVEMENTS IN MONKEYS
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DOI：
10.1152/jn.1994.72.1.150
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发表时间：
1994-07-01
影响因子：
2.5
通讯作者：
LISBERGER, SG
中科院分区：
文献类型：
--
作者：
KRAUZLIS, RJ;LISBERGER, SG
1.我们的目标是评估与图像速度变化相关的视觉运动信号是否有助于追踪眼动。我们记录了匀速坡道目标运动引起的平滑眼球运动。在两种不同类型的刺激中，目标运动的开始要么提供目标速度的突然阶跃变化，要么提供持续125ms的平稳目标加速，然后以恒定速度延长目标运动。我们测量了追逐的前100毫秒的眼球加速度。由于从视觉刺激开始到平稳眼球运动开始有100毫秒的潜伏期，在这100毫秒的间隔内的眼球加速度提供了驱动追逐的视觉运动通路的开环反应的估计。对于目标速度的步长，在追逐的前100毫秒内，眼球加速度取决于“运动起始延迟”，即目标出现和运动开始之间的间隔。如果运动开始延迟为>；100ms，则初始眼球运动由可分离的眼球加速的早期和晚期组成。在追踪开始后0~40ms这段时间内，早期阶段主导眼球加速，对图像速度相对不敏感。在追踪开始后的40-100ms之间，晚期占主导地位，并且其幅度与成像速度成正比。如果目标的出现和运动的开始之间没有延迟，则看不到早期成分，并且在前100ms的追逐中，眼球加速与目标的速度有关。对于目标速度的阶跃变化，追逐前40ms的眼球加速度与目标速度饱和&10度/S之间的关系。相反，在追逐开始后40-100ms的间隔内测量眼球加速度时，这种关系几乎是线性的。我们认为，前40ms的追踪是由与目标运动开始相关的瞬间视觉运动输入(运动开始瞬间成分)驱动的，而接下来的60ms是由持续的视觉运动输入(图像速度成分)驱动的。当目标在匀速运动前平稳加速125ms时，追逐的开始类似于目标速度阶跃引起的追逐。然而，对于平滑的目标加速，追踪潜伏期始终长于目标速度的步长。对于由目标速度阶跃引起的追踪后期成分，平滑目标加速度引起的眼动大于由眼球加速度与目标速度关系所预测的眼动。对于较小的目标加速度，实际眼球加速度与预测的眼球加速度之差急剧增加，当目标加速度较大时，眼球加速度与实际眼球加速度的差值趋于饱和。与图像速度的平滑变化相关的图像运动和/或持续的视觉响应。我们的行为观察为使用多个视觉运动输入的追逐模型提供了一个基于追逐眼动测量的理论基础。
1. Our goal was to assess whether visual motion signals related to changes in image velocity contribute to pursuit eye movements. We recorded the smooth eye movements evoked by ramp target motion at constant speed. In two different kinds of stimuli, the onset of target motion provided either an abrupt, step change in target velocity or a smooth target acceleration that lasted 125 ms followed by prolonged target motion at constant velocity. We measured the eye acceleration in the first 100 ms of pursuit. Because of the 100-ms latency from the onset of visual stimuli to the onset of smooth eye movement, the eye acceleration in this 100-ms interval provides an estimate of the open-loop response of the visuomotor pathways that drive pursuit.2. For steps of target velocity, eye acceleration in the first 100 ms of pursuit depended on the ''motion onset delay,'' defined as the interval between the appearance of the target and the onset of motion. If the motion onset delay was > 100 ms, then the initial eye movement consisted of separable early and late phases of eye acceleration. The early phase dominated eye acceleration in the interval from 0 to 40 ms after pursuit onset and was relatively insensitive to image speed. The late phase dominated eye acceleration in the interval 40-100 ms after the onset of pursuit and had an amplitude that was proportional to image speed. If there was no delay between the appearance of the target and the onset of its motion, then the early component was not seen, and eye acceleration was related to target speed throughout the first 100 ms of pursuit.3. For step changes of target velocity, the relationship between eye acceleration in the first 40 ms of pursuit and target velocity saturated at target speeds >10 degrees/s. In contrast, the relationship was nearly linear when eye acceleration was measured in the interval 40-100 ms after the onset of pursuit. We suggest that the first 40 ms of pursuit are driven by a transient visual motion input that is related to the onset of target motion (motion onset transient component) and that the next 60 ms are driven by a sustained visual motion input (image velocity component).4. When the target accelerated smoothly for 125 ms before moving at constant speed, the initiation of pursuit resembled that evoked by steps of target velocity. However, the latency of pursuit was consistently longer for smooth target accelerations than for steps of target velocity.5. The eye movements evoked by smooth target acceleration were larger than those predicted by the relationship between eye acceleration and target velocity for the late component of pursuit elicited by steps of target velocity. The difference between the actual and predicted eye acceleration increased steeply for small target accelerations and then saturated for higher values of target acceleration. image motion and/or sustained visual responses associated with smooth changes in image speed. Our behavioral observations provide a rationale, based on measurements of pursuit eye movements, for models of pursuit that use multiple visual motion inputs.