Wang Chin-An, Brien Donald C, Munoz Douglas P
Centre for Neuroscience Studies, Queen's University, Botterell Hall, 18 Stuart Street, Kingston, ON, K7L 3N6, Canada.
Eur J Neurosci. 2015 Apr;41(8):1102-10. doi: 10.1111/ejn.12883. Epub 2015 Mar 27.
The ability to generate flexible behaviors to accommodate changing goals in response to identical sensory stimuli is a signature that is inherited in humans and higher-level animals. In the oculomotor system, this function has often been examined with the anti-saccade task, in which subjects are instructed, prior to stimulus appearance, to either automatically look at the peripheral stimulus (pro-saccade) or to suppress the automatic response and voluntarily look in the opposite direction from the stimulus (anti-saccade). Distinct neural preparatory activity between the pro-saccade and anti-saccade conditions has been well documented, particularly in the superior colliculus (SC) and the frontal eye field (FEF), and this has shown higher inhibition-related fixation activity in preparation for anti-saccades than in preparation for pro-saccades. Moreover, the level of preparatory activity related to motor preparation is negatively correlated with reaction times. We hypothesised that preparatory signals may be reflected in pupil size through a link between the SC and the pupil control circuitry. Here, we examined human pupil dynamics during saccade preparation prior to the execution of pro-saccades and anti-saccades. Pupil size was larger in preparation for correct anti-saccades than in preparation for correct pro-saccades and erroneous pro-saccades made in the anti-saccade condition. Furthermore, larger pupil dilation prior to stimulus appearance accompanied saccades with faster reaction times, with a trial-by-trial correlation between dilation size and anti-saccade reaction times. Overall, our results demonstrate that pupil size is modulated by saccade preparation, and neural activity in the SC, together with the FEF, supports these findings, providing unique insights into the neural substrate coordinating cognitive processing and pupil diameter.
能够生成灵活行为以适应不断变化的目标，从而应对相同的感官刺激，这是人类和高等动物所共有的特征。在眼球运动系统中，这种功能通常通过反扫视任务来研究，在该任务中，在刺激出现之前，受试者被指示要么自动看向周边刺激（顺向扫视），要么抑制自动反应并自愿看向与刺激相反的方向（反向扫视）。顺向扫视和反向扫视条件下不同的神经准备活动已得到充分记录，特别是在上丘（SC）和额叶眼区（FEF），并且这表明在准备反向扫视时比准备顺向扫视时具有更高的与抑制相关的注视活动。此外，与运动准备相关的准备活动水平与反应时间呈负相关。我们假设准备信号可能通过SC与瞳孔控制电路之间的联系反映在瞳孔大小上。在这里，我们研究了人类在执行顺向扫视和反向扫视之前的扫视准备过程中的瞳孔动态。准备正确反向扫视时的瞳孔大小大于准备正确顺向扫视和在反向扫视条件下做出的错误顺向扫视时的瞳孔大小。此外，刺激出现前更大的瞳孔扩张伴随着反应时间更快的扫视，每次试验的瞳孔扩张大小与反向扫视反应时间之间存在相关性。总体而言，我们的结果表明瞳孔大小受扫视准备的调节，并且SC以及FEF中的神经活动支持了这些发现，为协调认知处理和瞳孔直径的神经基础提供了独特的见解。
