Li Hsin-Hung, Barbot Antoine, Carrasco Marisa
Department of Psychology, New York University, 6 Washington Place, New York, NY 10003, USA.
Department of Psychology, New York University, 6 Washington Place, New York, NY 10003, USA; Flaum Eye Institute, University of Rochester, 210 Crittenden Boulevard, Rochester, NY 14642, USA; Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA.
Curr Biol. 2016 Jun 20;26(12):1564-1570. doi: 10.1016/j.cub.2016.04.028. Epub 2016 Jun 2.
Human observers make large rapid eye movements-saccades-to bring behaviorally relevant information into the fovea, where spatial resolution is high. In some visual tasks [1-4], performance at the location of a saccade target improves before the eyes move. Although these findings provide evidence that extra-retinal signals evoked by saccades can enhance visual perception, it remains unknown whether and how presaccadic modulations change the processing of feature information and thus modulate visual representations. To answer this question, one must go beyond the use of methods that only probe performance accuracy (d') in different tasks. Here, using a psychophysical reverse correlation approach [5-8], we investigated how saccade preparation influences the processing of orientation and spatial frequency-two building blocks of early vision. We found that saccade preparation selectively enhanced the gain of high spatial frequency information and narrowed orientation tuning at the upcoming saccade landing position. These modulations were time locked to saccade onset, peaking right before the eyes moved (-50-0 ms). Moreover, merely deploying covert attention within the same temporal interval without preparing a saccade did not alter performance. The observed presaccadic tuning changes may correspond to the presaccadic enhancement [9-11] and receptive field shifts reported in neurophysiological studies [12-14]. Saccade preparation may support transaccadic integration by reshaping the representation of the saccade target to be more fovea-like just before the eyes move. The presaccadic modulations on spatial frequency and orientation processing illustrate a strong perception-action coupling by revealing that the visual system dynamically reshapes feature selectivity contingent upon eye movements.
人类观察者会进行大幅度的快速眼动——扫视，以便将行为相关信息带入中央凹，因为中央凹的空间分辨率很高。在一些视觉任务中[1 - 4]，扫视目标位置的表现会在眼睛移动之前得到改善。尽管这些发现提供了证据，表明扫视诱发的视网膜外信号可以增强视觉感知，但扫视前调制是否以及如何改变特征信息的处理从而调节视觉表征，仍然未知。为了回答这个问题，必须超越仅在不同任务中探测表现准确性（d'）的方法。在这里，我们使用心理物理学反向相关方法[5 - 8]，研究了扫视准备如何影响早期视觉的两个基本要素——方向和空间频率的处理。我们发现，扫视准备选择性地增强了高空间频率信息的增益，并在即将到来的扫视着陆位置缩小了方向调谐。这些调制与扫视开始时间锁定，在眼睛移动前达到峰值（-50 - 0毫秒）。此外，仅仅在相同的时间间隔内进行隐蔽注意而不准备扫视并不会改变表现。观察到的扫视前调谐变化可能与神经生理学研究[12 - 14]中报道的扫视前增强[9 - 11]和感受野转移相对应。扫视准备可能通过在眼睛移动前将扫视目标的表征重塑得更像中央凹，来支持跨扫视整合。对空间频率和方向处理的扫视前调制通过揭示视觉系统根据眼动动态重塑特征选择性，说明了一种强大的感知 - 行动耦合。
