Department of Psychological and Brain Sciences, Boston University, 2 Cummington Mall, Boston, MA 02215, USA.
Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.
Curr Biol. 2017 May 8;27(9):1268-1277. doi: 10.1016/j.cub.2017.03.034. Epub 2017 Apr 20.
Much evidence indicates that humans and other species process large-scale visual information before fine spatial detail. Neurophysiological data obtained with paralyzed eyes suggest that this coarse-to-fine sequence results from spatiotemporal filtering by neurons in the early visual pathway. However, the eyes are normally never stationary: rapid gaze shifts (saccades) incessantly alternate with slow fixational movements. To investigate the consequences of this oculomotor cycle on the dynamics of perception, we combined spectral analysis of visual input signals, neural modeling, and gaze-contingent control of retinal stimulation in humans. We show that the saccade/fixation cycle reformats the flow impinging on the retina in a way that initiates coarse-to-fine processing at each fixation. This finding reveals that the visual system uses oculomotor-induced temporal modulations to sequentially encode different spatial components and suggests that, rather than initiating coarse-to-fine processing, spatiotemporal coupling in the early visual pathway builds on the information dynamics of the oculomotor cycle.
大量证据表明，人类和其他物种在处理精细空间细节之前会处理大规模的视觉信息。通过对瘫痪眼睛获得的神经生理学数据进行研究，表明这种从粗到细的顺序是由早期视觉通路中的神经元进行时空滤波的结果。然而，眼睛通常不会静止不动：快速眼球运动（扫视）与缓慢的注视运动不断交替。为了研究这个眼球运动周期对视知觉动态的影响，我们结合了视觉输入信号的频谱分析、神经建模以及人类注视相关的视网膜刺激控制。我们表明，扫视/注视周期以一种在每次注视时启动从粗到细处理的方式重新格式化作用在视网膜上的光流。这一发现表明，视觉系统利用眼球运动引起的时间调制来依次编码不同的空间成分，并表明，早期视觉通路中的时空耦合不是启动从粗到细的处理，而是建立在眼球运动周期的信息动态基础上的。
