Lack of sleep disrupts brain regions that prevent unwanted memories from forming.

Sleep issues play a significant role in the onset and persistence of various mental disorders, yet the reason for this connection remains unclear.

A new study published in the journal Proceedings of the National Academy of Sciences (PNAS) offers fresh insights into the cognitive and neural mechanisms underlying the relationship between sleep and mental health. These findings may aid in developing new treatment methods and prevention strategies for mental health issues such as depression and anxiety.

Dr. Marcus Harrington, who conducted this research, is a lecturer at the UEA School of Psychology and the lead author of the paper titled “Memory Control Deficits in the Human Brain Suffering from Sleep Deprivation.” For this study, he collaborated with colleagues from the universities of York, Cambridge, Sussex, and Queen's University (Canada).

Functional neuroimaging has revealed for the first time that memory control deficits following sleep deprivation are linked to difficulties in engaging brain regions that support the inhibition of memory retrieval, and that the nightly recovery of these brain areas is associated with rapid eye movement (REM) sleep.

Considering that memories play a central role in our emotional perception of the external world, disruptions in memory control may largely explain the connection between sleep loss and emotional regulation impairment.

A better understanding of the mechanisms that lead to intrusive memories is crucial for improving emotional well-being and reducing the global burden of mental disorders.

In this study, eighty-five healthy adults attempted to suppress unwanted memories while their brains were scanned using functional magnetic resonance imaging. Half of the participants had a good night's sleep in the sleep lab before the task, while the other half stayed awake all night.

During memory suppression, well-rested participants exhibited greater activity in the right dorsolateral prefrontal cortex—a brain region that regulates thoughts, actions, and emotions—compared to those who had been awake all night. The rested participants also showed reduced activity in the hippocampus—a brain area involved in memory retrieval—while attempting to suppress unwanted memories.

Among the participants who slept in the lab, those who spent more time in REM sleep better engaged the right dorsolateral prefrontal cortex during memory suppression, indicating the role of REM sleep in restoring the prefrontal control mechanisms that underlie the ability to prevent unwanted memories from entering consciousness.

The lead researcher stated, “Overall, our results highlight the critical role of sleep in maintaining control over our memories and current thoughts.”