London, UK: A study from the University of East Anglia (UEA) has found that sleep loss can impair memory control and contribute to mental health issues by affecting brain regions responsible for managing unwanted memories.
While sleep disturbances are known to contribute to the onset and persistence of mental health conditions, the mechanisms behind this connection have remained unclear.
A study published in Proceedings of the National Academy of Sciences (PNAS) offers new insights into the cognitive and neural processes connecting sleep with mental health, which could help inform the development of new treatments for conditions such as depression and anxiety.
Dr. Marcus Harrington, a Lecturer in UEA’s School of Psychology and lead author of the study “Memory control deficits in the sleep-deprived human brain,” conducted the research in collaboration with colleagues from York, Cambridge, Sussex, and Queen’s University (Canada).
REM Sleep’s Role
The study used functional neuroimaging to reveal for the first time that sleep deprivation disrupts brain regions that help inhibit memory retrieval, making it harder to control unwanted thoughts.
The findings show that the rejuvenation of these brain regions, which are essential for memory control, occurs during rapid eye movement (REM) sleep.
Dr. Harrington explained that unpleasant memories can intrude into consciousness, especially in individuals with mental health disorders like depression, anxiety, and PTSD. Such intrusive memories can be recurrent and disturbing, significantly affecting emotional well-being.
Impact of Sleep
The study involved 85 healthy adults, half of whom had a restful sleep before the task, and the other half remained awake. While attempting to suppress unwanted memories, well-rested participants showed more activation in the right dorsolateral prefrontal cortex, a brain region that manages thoughts, emotions, and actions.
This was in contrast to those who had stayed awake, who exhibited reduced activation in this region. Additionally, the rested participants displayed lower hippocampal activity during memory suppression, which suggests that sleep aids in controlling memory retrieval.
Among the well-rested participants, those who spent more time in REM sleep demonstrated better engagement of the prefrontal cortex, which is crucial for memory control, reinforcing the role of REM sleep in restoring the brain’s ability to prevent unwanted thoughts.
Dr. Harrington emphasized that these findings highlight the importance of sleep in regulating memory and emotional processes, providing a better understanding of how sleep loss could contribute to emotional dysregulation and mental health problems.