Centre for Neuroscience Studies, Queen's University, Kingston, Ontario K7L 3N6, Canada, and Department of Computer Science, University of Southern California, Los Angeles, California 90089-0781.
J Neurosci. 2014 Jan 8;34(2):408-17. doi: 10.1523/JNEUROSCI.3550-13.2014.
The sudden appearance of a novel stimulus in the environment initiates a series of orienting responses that include coordinated shifts of gaze and attention, and also transient changes in pupil size. Although numerous studies have identified a significant effect of stimulus saliency on shifts of gaze and attention, saliency effects on pupil size are less understood. To examine salience-evoked pupil responses, we presented visual, auditory, or audiovisual stimuli while monkeys fixated a central visual spot. Transient pupil dilation was elicited after visual stimulus presentation regardless of target luminance relative to background, and auditory stimuli also evoked similar pupil responses. Importantly, the evoked pupil response was modulated by contrast-based saliency, with faster and larger pupil responses following the presentation of more salient stimuli. The initial transient component of pupil dilation was qualitatively similar to that evoked by weak microstimulation of the midbrain superior colliculus. The pupil responses elicited by audiovisual stimuli were well predicted by a linear summation of each modality response. Together, the results suggest that the transient pupil response, as one component of orienting, is modulated by contrast-based saliency, and the superior colliculus is likely involved in its coordination.
环境中突然出现新颖刺激会引发一系列定向反应，包括眼球和注意力的协调转移，以及瞳孔大小的短暂变化。尽管许多研究已经确定了刺激显著性对眼球和注意力转移的显著影响，但对瞳孔大小的显著性影响了解较少。为了研究显著性诱发的瞳孔反应，我们在猴子注视中央视觉点的同时呈现视觉、听觉或视听刺激。无论目标亮度相对于背景如何，视觉刺激呈现后都会引起瞳孔短暂扩张，听觉刺激也会引起类似的瞳孔反应。重要的是，诱发的瞳孔反应受到基于对比度的显著性的调制，呈现更显著的刺激会引起更快和更大的瞳孔反应。瞳孔扩张的初始瞬态分量与中脑上丘弱微刺激引起的瞳孔反应定性相似。视听刺激引起的瞳孔反应可以很好地通过每种模态反应的线性求和来预测。总的来说，结果表明，作为定向的一个组成部分，瞬态瞳孔反应受到基于对比度的显著性的调制，而上丘可能参与了其协调。
