A new study led by the University of East Anglia unveils how sleep, especially REM sleep, plays a crucial role in preventing unwanted memories from intruding into our thoughts, with implications for mental health treatments.
Researchers led by the University of East Anglia (UEA) have made an intriguing discovery that could pave the way for innovative mental health treatments. Their recent study connects poor sleep with deficits in brain regions responsible for keeping unwanted thoughts at bay, shedding light on why sleep problems often correlate with mental health issues.
Published in the Proceedings of the National Academy of Sciences (PNAS), this new research identifies the cognitive and neural mechanisms linking sleep and mental health. The findings could lead to new strategies for addressing conditions such as depression, anxiety and post-traumatic stress disorder (PTSD).
Led by Marcus Harrington, a lecturer at UEA’s School of Psychology, the research employed functional neuroimaging to observe brain activity related to memory control during sleep deprivation.
“Memories of unpleasant experiences can intrude into conscious awareness, often in response to reminders,” Harrington said in a news release. “While such intrusive memories are an occasional and momentary disturbance for most people, they can be recurrent, vivid and upsetting for individuals suffering from mental health disorders, such as depression, anxiety and post-traumatic stress disorder.”
Eighty-five healthy adults participated in the study, attempting to suppress unwanted memories while their brain activity was imaged using functional MRI (fMRI). Half of the participants had a restful night’s sleep in a sleep lab, while the other half remained awake all night.
The well-rested participants showed significantly higher activity in the right dorsolateral prefrontal cortex — a brain area governing thoughts, actions and emotions — compared to those who were sleep-deprived.
Additionally, those who slept exhibited lower activity in the hippocampus, a region essential for memory retrieval, during attempts to suppress unwanted memories.
Among those who slept, individuals who enjoyed more time in rapid eye movement (REM) sleep demonstrated better engagement of the prefrontal cortex during memory suppression, suggesting REM sleep’s role in rejuvenating brain areas necessary for controlling intrusive memories.
“Given that memories play a central role in our affective perception of the external world, memory control failures may go a long way towards explaining the relationship between sleep loss and emotional dysregulation,” Harrington added. “A better understanding of the mechanisms that precipitate the occurrence of intrusive memories is vital to improving emotional well-being and reducing the global burden of mental illness.”
He concluded by adding, “Taken together, our findings highlight the critical role of sleep in maintaining control over both our memories and ongoing thoughts.”