Eyes Wide Open

In this talk, I will discuss how we can use the eyes’ pupils as a window into the brain’s arousal system. Our state of arousal—how awake, alert, and focused we are—strongly influences our daily functioning. Through biofeedback training based on real-time pupil signals, individuals can learn to take control of their arousal state. Drawing from experiments conducted in our lab, I will showcase examples of how changes in pupil size relate to changes in brain and body physiology, as well as behavioural responses, offering insights into how we can learn to regulate our mental state.

The eye is strongly linked to brain health during wakefulness, but what about during sleep? With an aging population and societal constraints that disrupt sleep, sleep disorders are increasingly prevalent, but the brain mechanisms behind sleep disorders remain unclear. The relationship between the eye and the brain has been studied through infrared eye tracking technology. However, the interplay between these systems during sleep has remained hidden behind closed eyelids. By taping one eye open during sleep, we could monitor pupil size changes, which closely reflect the activity of deep-brain circuits that regulate sleep. These findings could enable new avenues to better understand sleep-related pathologies and to detect them earlier.