The Pupil‐Brain System at Rest: Spontaneous Pupil Fluctuations as Markers of Neuromodulatory and Network Dynamics
Psychophysiology June 1, 2026 Tongxin Liu, Sonja A. Kotz, Antonio Criscuolo et al. 1 citation
Spontaneous pupil fluctuations during rest offer a non-invasive, low-cost index of central arousal dynamics. This review synthesizes evidence on the resting-state pupil-brain system, focusing on central neuromodulatory circuits and large-scale cortical networks. It examines the relationship between pupil fluctuations and the ascending arousal system, including noradrenergic, cholinergic, serotonergic, and dopaminergic nuclei, and details coupling with intrinsic functional networks—default mode, salience, and sensorimotor systems. Converging evidence from animal and human neuroimaging studies reveals robust spatiotemporal and spectral coupling between pupil fluctuations and neural activity across micro- and macro-scales. The findings support a systems-level framework where pupil fluctuations serve as integrative markers linking subcortical neuromodulation with large-scale cortical dynamics, with potential utility as biomarkers for neuropsychiatric conditions and altered states of consciousness.