Researchers observe pupils during sleep

(CONNECT) Researchers from the Neural Control of Movement Lab at the Swiss Federal Institute of Technology in Zurich (ETH) have been able to observe the pupil movements of sleeping people over several hours for the first time. They discovered that the size of the pupil constantly fluctuates during sleep. This reflects the state of arousal and the activation level of brain regions that are responsible for sleep-wake regulation.

"These observations contradict the previous assumption that arousal levels are generally low during sleep," one of the study leaders, Caroline Lustenberger, is quoted as saying in an ETH report. By measuring pupil activity during sleep, the team may be able to detect sleep disorders caused by diseases such as post-traumatic stress disorder or insomnia.

The study showed that pupil dynamics are not only related to the different stages of sleep, but also to specific patterns of brain activity. In addition, the researchers discovered that the brain reacts differently to sounds - depending on the level of activation, which is reflected in the pupil size. The study has been published in the journal "Nature Communications".

They now want to use medication to find out whether a specific brain region, the locus coeruleus, is actually responsible for controlling the pupils during sleep and how changes in the activation level affect sleep and its functions. Another aim is to make the technology usable outside the sleep laboratory, for example in hospitals. There, it could help to monitor the waking of coma patients or to diagnose sleep disorders more accurately. ce/mm