Processing of retinal and extraretinal signals for memory-guided saccades during smooth pursuit
Processing of retinal and extraretinal signals for memory-guided saccades during smooth pursuit
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DOI：
10.1152/jn.00543.2004
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发表时间：
2005-03-01
影响因子：
2.5
通讯作者：
Lefèvre, P
中科院分区：
文献类型：
--
作者：
Blohm, G;Missal, M;Lefèvre, P
跟踪自身运动以保持空间恒定性是视觉系统的一个基本特征。因此，扫视系统使用关于先前扫视的视网膜外信息来更新记忆目标的内部表示，这是在行为和电生理学研究中已经确定的能力。然而，在记忆引导的眼跳的潜伏期诱导的平滑眼球运动产生了矛盾的结果。事实上，一些研究描述了空间准确的扫视，而另一些报告视网膜编码的扫视。今天，在没有视觉的情况下，扫视系统如何跟踪平稳的眼球运动仍然不清楚。在这里，我们开发了一个原始的二维行为范例，以进一步研究如何平滑的眼睛位移可以补偿，以确保空间恒定性。人类受试者被要求追踪一个移动的目标，并将他们的眼睛对准记忆中的位置。第二个目标（闪光）一旦出现，就会被短暂呈现。第一方向眼跳的分析揭示了一个双峰潜伏期分布相关的两种不同的眼跳编程策略。短潜伏期（175毫秒）扫视使用视网膜外信息的平稳眼位移在潜伏期的程序空间更准确的扫视。在闪光灯的时刻的感觉参数（视网膜位置误差和眼速度）影响这两种策略之间的选择。我们假设，这种扫视反应的速度和准确性之间的权衡揭示了存在两个耦合的神经通路扫视编程。快速纹状体-丘通路可能只使用关于闪光位置的视网膜信息来编程第一次扫视。较慢的路径可能涉及后顶叶皮层，一旦视网膜外平滑的眼睛位移信息变得可用于系统，则更新闪光的内部表示。
It is an essential feature for the visual system to keep track of self-motion to maintain space constancy. Therefore the saccadic system uses extraretinal information about previous saccades to update the internal representation of memorized targets, an ability that has been identified in behavioral and electrophysiological studies. However, a smooth eye movement induced in the latency period of a memory-guided saccade yielded contradictory results. Indeed some studies described spatially accurate saccades, whereas others reported retinal coding of saccades. Today, it is still unclear how the saccadic system keeps track of smooth eye movements in the absence of vision. Here, we developed an original two-dimensional behavioral paradigm to further investigate how smooth eye displacements could be compensated to ensure space constancy. Human subjects were required to pursue a moving target and to orient their eyes toward the memorized position of. a briefly presented second target (flash) once it appeared. The analysis of the first orientation saccade revealed a bimodal latency distribution related to two different saccade programming strategies. Short-latency (175 ms) saccades used extraretinal information about the smooth eye displacement during the latency period to program spatially more accurate saccades. Sensory parameters at the moment of the flash (retinal position error and eye velocity) influenced the choice between both strategies. We hypothesize that this tradeoff between speed and accuracy of the saccadic response reveals the presence of two coupled neural pathways for saccadic programming. A fast striatal-collicular pathway might only use retinal information about the flash location to program the first saccade. The slower pathway could involve the posterior parietal cortex to update the internal representation of the flash once extraretinal smooth eye displacement information becomes available to the system.