Richard Alby, Churan Jan, Guitton Daniel E, Pack Christopher C
Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
J Vis. 2011 Oct 6;11(12):1. doi: 10.1167/11.12.1.
In primates, inspection of a visual scene is typically interrupted by frequent gaze shifts, occurring at an average rate of three to five times per second. Perceptually, these gaze shifts are accompanied by a compression of visual space toward the saccade target, which may be attributed to an oculomotor signal that transiently influences visual processing. While previous studies of compression have focused exclusively on saccadic eye movements made with the head artificially immobilized, many brain structures involved in saccade generation also encode combined eye-head gaze shifts. Thus, in order to understand the interaction between gaze motor and visual signals, we studied perception during eye-head gaze shifts and found a powerful compression of visual space that was spatially directed toward the intended gaze (and not the eye movement) target location. This perceptual compression was nearly constant in duration across gaze shift amplitudes, suggesting that the signal that triggers compression is largely independent of the size and kinematics of the gaze shift. The spatial pattern of results could be captured by a model that involves interactions, on a logarithmic map of visual space, between two loci of neural activity that encode the gaze shift vector and visual stimulus position relative to the fovea.
在灵长类动物中，对视觉场景的观察通常会被频繁的目光转移打断，目光转移的平均频率为每秒三到五次。从感知上来说，这些目光转移伴随着视觉空间向扫视目标的压缩，这可能归因于一种短暂影响视觉处理的眼动信号。虽然之前关于压缩的研究仅专注于头部人为固定时的眼球扫视运动，但许多参与扫视生成的脑结构也对眼球-头部联合目光转移进行编码。因此，为了理解目光运动和视觉信号之间的相互作用，我们研究了眼球-头部目光转移过程中的感知，发现了一种强大的视觉空间压缩，其在空间上指向预期的目光（而非眼球运动）目标位置。这种感知压缩在不同目光转移幅度下的持续时间几乎恒定，这表明触发压缩的信号在很大程度上与目光转移的大小和运动学无关。结果的空间模式可以通过一个模型来捕捉，该模型涉及在视觉空间的对数图上，对编码目光转移向量和相对于中央凹的视觉刺激位置的两个神经活动位点之间的相互作用。
