Pupil and gaze during binocular rivalry

The pupil provides a rich, non-invasive measure of the neural bases of perception and cognition, and has been of particular value in uncovering the role of arousal-linked neuromodulation, which alters cortical processing as well as pupil size. But pupil size is subject to a multitude of influences, which complicates unique interpretation. We measured pupils of observers experiencing perceptual multistability -- an ever-changing subjective percept in the face of unchanging but inconclusive sensory input. In separate conditions the endogenously generated perceptual changes were either task-relevant or not, allowing a separation between perception-related and task-related pupil signals. Perceptual changes were marked by a complex pupil response that could be decomposed into two components: a dilation tied to task execution and plausibly indicative of an arousal-linked noradrenaline surge, and an overlapping constriction tied to the perceptual transient and plausibly a marker of altered visual cortical representation. Constriction, but not dilation, amplitude systematically depended on the time interval between perceptual changes, possibly providing an overt index of neural adaptation. These results show that the pupil provides a simultaneous reading on interacting but dissociable neural processes during perceptual multistability, and suggest that arousal-linked neuromodulation shapes action but not perception in these circumstances.

Methods
Details about the collection of these data can be found in the published article.

瞳孔是一种非侵入性的丰富观测手段，可用于探究感知与认知的神经基础，在揭示唤醒相关神经调节（arousal-linked neuromodulation）的作用方面具有独特价值——这类调节不仅会改变瞳孔大小，还会调控皮层加工过程。但瞳孔大小易受多种因素影响，这为单一化的结果解读带来了阻碍。我们对处于知觉多稳态（perceptual multistability）状态下的观察者的瞳孔进行了测量：知觉多稳态指的是，当感官输入恒定却模棱两可时，个体的主观感知会持续发生变化。在不同实验条件下，内源性产生的感知变化可分为与任务相关和无关两类，这使得我们能够分离出与感知相关以及与任务相关的瞳孔信号。感知变化伴随有复杂的瞳孔反应，该反应可分解为两个成分：一是与任务执行相关的瞳孔扩大，其大概率反映了与唤醒相关的去甲肾上腺素（noradrenaline）激增；二是与感知瞬变相伴随的瞳孔缩小，其可能是视觉皮层表征发生改变的显性指标。瞳孔缩小的幅度（而非扩大幅度）会随感知变化的间隔时间呈现系统性变化，这或许可作为神经适应的显性观测指标。上述研究结果表明，在知觉多稳态过程中，瞳孔能够同时反映出既相互作用又可分离的神经活动过程；同时也提示，在这类情境下，唤醒相关神经调节会调控行为，但不会直接影响感知。
方法
有关这些数据的采集细节，请参阅已发表的研究论文。