Summary: Researchers unveiled a critical link between breathing and memory consolidation during sleep. In an extensive study involving EEG and breathing analysis, they discovered that specific sleep-related brain rhythms are directly influenced by our breathing patterns.
These findings highlight the importance of respiration in reinforcing learned information while we sleep. This work could have significant implications for addressing age-related memory issues and sleep disorders.
Key Facts:
- The study found a direct correlation between specific brain rhythms during sleep and the process of memory consolidation.
- This research provides evidence that our breathing patterns play a crucial role in how memories are reinforced during sleep.
- The findings suggest potential new treatments for sleep and memory disorders, particularly in older adults.
Source: LMU
How are memories consolidated during sleep?
In 2021, researchers led by Dr. Thomas Schreiner, leader of the Emmy Noether junior research group at LMU’s Department of Psychology, had already shown there was a direct relationship between the emergence of certain sleep-related brain activity patterns and the reactivation of memory contents during sleep.
However, it was still unclear whether these rhythms are orchestrated by a central pacemaker. So the researchers joined up with scientists from the Max Planck Institute for Human Development in Berlin and the University of Oxford to reanalyze the data. Their results have identified respiration as a potential pacemaker.
“That is to say, our breathing influences how memories are consolidated during sleep,” says Schreiner.
Learning processes investigated in sleep laboratory
For their original study, the researchers showed 20 study participants 120 images over the course of two sessions. All the pictures were associated with certain words. Then the participants slept for around two hours in the sleep laboratory.
When they awoke, they were questioned about the associations they had learned. During the entire learning and sleep period, their brain activity was recorded by means of EEG, along with their breathing.
The researchers discovered that previously learned contents were spontaneously reactivated by the sleeping brain during the presence of so-called slow oscillations and sleep spindles (short phases of increased brain activity).
“The precision of the coupling of these sleep-related brain rhythms increases from childhood to adolescence and then declines again during aging,” says Schreiner.
Breathing and brain activity are linked
Because respiration frequency also changes with age, the researchers then analyzed the data in relation to the recorded breathing and were able to establish a connection between them.
“Our results show that our breathing and the emergence of characteristic slow oscillation and spindle patterns are linked,” says Schreiner.
“Although other studies had already established a connection between breathing and cognition during wake, our work makes clear that respiration is also important for memory processing during sleep.”
Older people often suffer from sleep disorders, respiratory disorders, and declining memory function. Schreiner plans to further investigate whether there are connections between these phenomena and whether interventions – such as the use of CPAP masks, which are already used to treat sleep apnea – make sense from a cognitive perspective.
About this sleep and memory research news
Author: Constanze Drewlo
Source: LMU
Contact: Constanze Drewlo – LMU
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Respiration modulates sleep oscillations and memory reactivation in humans” by Thomas Schreiner et al. Nature Communications
Abstract
Respiration modulates sleep oscillations and memory reactivation in humans
The beneficial effect of sleep on memory consolidation relies on the precise interplay of slow oscillations and spindles. However, whether these rhythms are orchestrated by an underlying pacemaker has remained elusive.
Here, we tested the relationship between respiration, which has been shown to impact brain rhythms and cognition during wake, sleep-related oscillations and memory reactivation in humans.
We re-analysed an existing dataset, where scalp electroencephalography and respiration were recorded throughout an experiment in which participants (N = 20) acquired associative memories before taking a nap.
Our results reveal that respiration modulates the emergence of sleep oscillations. Specifically, slow oscillations, spindles as well as their interplay (i.e., slow-oscillation_spindle complexes) systematically increase towards inhalation peaks.
Moreover, the strength of respiration – slow-oscillation_spindle coupling is linked to the extent of memory reactivation (i.e., classifier evidence in favour of the previously learned stimulus category) during slow-oscillation_spindles.
Our results identify a clear association between respiration and memory consolidation in humans and highlight the role of brain-body interactions during sleep.
