Psychological & Brain Sciences, Boston University, Boston, MA, USA.
Center for Systems Neuroscience, Boston University, Boston, MA, USA.
Sci Rep. 2024 Sep 19;14(1):21895. doi: 10.1038/s41598-024-70895-5.
Pupillometry is widely used to measure arousal states. The primary functional role of the pupil, however, is to respond to the luminance of visual inputs. We previously demonstrated that cognitive effort-related arousal interacted multiplicatively with luminance, with the strongest pupillary effects of arousal occurring at low-to-mid luminances (< 37 cd/m), implying a narrow range of conditions ideal for assessing cognitive arousal-driven pupillary differences. Does this generalize to other forms of arousal? To answer this, we assessed luminance-driven pupillary response functions while manipulating emotional arousal, using well-established visual and auditory stimulus sets. At the group level, emotional arousal interacted with the pupillary light response differently from cognitive arousal: the effects occurred primarily at much lower luminances (< 20 cd/m). Analyses at the individual-participant level revealed qualitatively distinct patterns of modulation, with a sizable number of individuals displaying no arousal response to the visual or auditory stimuli, regardless of luminance. Together, our results suggest that effects of arousal on pupil size are not monolithic: different forms of arousal exert different patterns of effects. More practically, our findings suggest that lower luminances create better conditions for measuring pupil-linked arousal, and when selecting ambient luminance levels, consideration of the arousal manipulation and individual differences is critical.
瞳孔测量被广泛用于测量觉醒状态。然而，瞳孔的主要功能作用是对视觉输入的亮度做出反应。我们之前的研究表明，认知努力相关的觉醒与亮度呈乘法交互作用，在低至中亮度（<37 cd/m）时，觉醒的瞳孔效应最强，这意味着存在一个理想的狭窄范围的条件，可用于评估认知唤醒驱动的瞳孔差异。这是否适用于其他形式的唤醒？为了回答这个问题，我们使用了经过验证的视觉和听觉刺激集，在操纵情绪唤醒的同时评估了亮度驱动的瞳孔反应功能。在群体水平上，情绪唤醒与瞳孔光反应的相互作用与认知唤醒不同：这种影响主要发生在低得多的亮度（<20 cd/m）。在个体参与者水平上的分析揭示了不同的调制模式，很大一部分个体对视觉或听觉刺激没有表现出任何唤醒反应，无论亮度如何。总之，我们的结果表明，唤醒对瞳孔大小的影响并不是单一的：不同形式的唤醒会产生不同的影响模式。更实际的是，我们的发现表明，较低的亮度可以创造更好的条件来测量与瞳孔相关的唤醒，并且在选择环境亮度水平时，需要考虑唤醒的操纵和个体差异。
