Research sheds new light on brain-heart interactions during sleep

A discovery by researchers from the GIGA - Center of Research Cyclotron at University of Liège reveals that the sleeping body also reacts to the external world during sleep, explaining how some information from the sensory environment can affect sleep quality.

Researchers at ULiège have collaborated with the University of Fribourg in Switzerland to investigate whether the body is truly disconnected from the external world during sleep. To do so, they focused on how heartbeat changes when we hear different words during sleep. They found that relaxing words slowed down cardiac activity as a reflection of deeper sleep and in comparison to neutral words that did not have such a slowing effect. This discovery is presented in Journal of Sleep Research and sheds new light on brain-heart interactions during sleep.

Matthieu Koroma (Fund for Scientific Research – FNRS postdoctoral researcher), Christina Schmidt and Athena Demertzi (both Fund for Scientific Research – FNRS Research Associate) from the GIGA Cyclotron Research Center at ULiège teamed up with colleagues from University of Fribourg led a previous study analyzing brain data (electroencephalogram) showing that relaxing words increased deep sleep duration and sleep quality, showing that we can positively influence sleep using meaningful words. By that time, the authors hypothesized that the brain also remains able to interpret sensory information in a way that makes our body more relaxed after hearing relaxing words during sleep. In this new study, the authors had the opportunity to analyze cardiac activity (electrocardiogram) to test this hypothesis and found that the heart slows down its activity only after the presentation of relaxing, but not control words.

Markers of both cardiac and brain activity were then compared to disentangle how much they contributed to the modulation of sleep by auditory information. Cardiac activity has been indeed proposed to directly contribute to the way we perceive the world, but such evidence was so far obtained in wakefulness. With these results, the ULiège researchers showed that it was also true in sleep, offering a new perspective on the essential role of bodily reactions beyond brain data for our understanding of sleep.

Most of sleep research focuses on the brain and rarely investigates bodily activity."

Dr. Christina Schmidt, GIGA Cyclotron Research Center at ULiège 

"We nevertheless hypothesize that the brain and the body are connected even when we cannot fully communicate, including sleep. Both brain and body information need then to be taken into account for a full understanding of how we think and react to our environment", explains Dr. Demertzi.

"We shared freely our methodology following the principles of Open Science hoping that the tools that helped to make this discovery will inspire other researchers to study the role played by the heart in other sleep functions", Dr.Koroma advocates.

This work offers a more comprehensive approach about the modulation of sleep functions by sensory information. By looking into the cardiac responses to sounds, we may, for example, study in the future the role of the body in the way sounds influence emotional processing of memories during sleep.

Source:
Journal reference:

Koroma, M., et al. (2024). Probing the embodiment of sleep functions: Insights from cardiac responses to word‐induced relaxation during sleep. Journal of Sleep Research. doi.org/10.1111/jsr.14160.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment
Post

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Online microaggressions impact sleep quality in young Black women