Temporal dynamics of saccades explained by a self-paced process
Temporal dynamics of saccades explained by a self-paced process
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DOI：
10.1038/s41598-017-00881-7
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发表时间：
2017-04-20
影响因子：
4.6
通讯作者：
Yuval-Greenberg, Shlomit
中科院分区：
文献类型：
--
作者：
Amit, Roy;Abeles, Dekel;Yuval-Greenberg, Shlomit
感觉器官被认为是有节奏地对环境进行采样，从而提供周期性的感知输入。搅拌和嗅闻是由振荡器控制的，振荡器对感觉获取的运动控制施加节奏，从而对感觉输入施加节奏。扫视眼球运动是灵长类动物主要的视觉采样机制，并被认为是构成这种节律性探索系统的一部分。在这项研究中，我们的特点扫视节奏，并检查是否是一致的自主振荡发生器或与自我步速生成。当观察者自由观看电影或注视静态刺激时，眼睛运动被跟踪。我们检查了探索性和注视性眼跳的时间动态，并量化了它们的一阶和高阶依赖关系。使用来自尖峰序列分析的方法分析数据，并针对数学模型和模拟进行测试。研究结果表明，眼跳的时间解释的一阶依赖性，特别是他们的不应期。扫视定时与自主起搏器不一致，但与“自定步调”发生器一致，其中每个扫视是依赖于扫视本身的结果的神经过程链中的一个环节。我们提出了一个数学模型，粗略地捕捉了眼跳计时的各个方面，并提出了产生所观察到的动态的可能神经机制。
Sensory organs are thought to sample the environment rhythmically thereby providing periodic perceptual input. Whisking and sniffing are governed by oscillators which impose rhythms on the motor-control of sensory acquisition and consequently on sensory input. Saccadic eye movements are the main visual sampling mechanism in primates, and were suggested to constitute part of such a rhythmic exploration system. In this study we characterized saccadic rhythmicity, and examined whether it is consistent with autonomous oscillatory generator or with self-paced generation. Eye movements were tracked while observers were either free-viewing a movie or fixating a static stimulus. We inspected the temporal dynamics of exploratory and fixational saccades and quantified their first-order and high-order dependencies. Data were analyzed using methods derived from spike-train analysis, and tested against mathematical models and simulations. The findings show that saccade timings are explained by first-order dependencies, specifically by their refractory period. Saccade-timings are inconsistent with an autonomous pace-maker but are consistent with a "self-paced" generator, where each saccade is a link in a chain of neural processes that depend on the outcome of the saccade itself. We propose a mathematical model parsimoniously capturing various facets of saccade-timings, and suggest a possible neural mechanism producing the observed dynamics.