Aperiodic pupil fluctuations at rest predict orienting of visual attention

Abstract

The aperiodic exponent of neural signals in different modalities is associated with the excitation/inhibition balance of the neural system. Given that resting pupil fluctuations contain rich temporal dynamics, we hypothesized that the aperiodic exponent of pupil fluctuations could predict the neural excitation/inhibition balance in attentional processing. The present study was the first attempt to investigate the cognitive significance of the aperiodic exponent of pupil responses. We recorded participants' resting pupil fluctuations and measured their visual attention with a Posner cueing task. Significant correlations were found between the aperiodic exponent of pupil fluctuations and microsaccadic and behavioral responses when stimulus uncertainty was high and thus required a neural excitation/inhibition balance. Furthermore, an independent analysis showed that the aperiodic exponent of pupil fluctuations was predictive of an individual's ADHD symptoms of hyperactivity/impulsivity, suggesting its potential to reflect an individual's trait of attentional processing. These findings highlight the rich information contained in pupil fluctuations and open a new avenue for accessing the neural excitation/inhibition balance in cognitive processing.