The relationship between inadequate sleep and mental health issues may stem from impairments in brain areas responsible for blocking undesirable thoughts, according to a study conducted by the University of East Anglia (UEA).
Sleep disturbances are key factors in the development and persistence of various mental health conditions, yet the exact reasons for this association remain unclear.
A recent publication in the Proceedings of the National Academy of Sciences (PNAS) sheds light on the cognitive and neural processes that link sleep disturbances with mental health. These insights could pave the way for new therapeutic approaches and preventative measures for mental health issues like depression and anxiety.
Dr Marcus Harrington, a lecturer at UEA’s School of Psychology and the lead author of the study titled ‘Memory control deficits in the sleep-deprived human brain’, collaborated with colleagues from York, Cambridge, Sussex, and Queen’s University in Canada.
For the first time, functional neuroimaging has revealed that the inability to control memories following sleep deprivation is due to difficulties activating brain regions that inhibit memory retrieval. Furthermore, restoring these brain regions overnight is associated with rapid eye movement (REM) sleep.
Dr Harrington explained: “Memories of unpleasant experiences can pop into our minds, often triggered by reminders. While such intrusive memories are brief and infrequent disturbances for most, they can be persistent, vivid, and distressing for those with mental health disorders such as depression, anxiety, and post-traumatic stress disorder.
“The failure to control these memories can significantly influence our emotional perception of the world around us, which may explain the link between sleep loss and emotional disturbances.
“Understanding the mechanisms that lead to intrusive memories is crucial for enhancing emotional wellbeing and reducing the widespread impact of mental health conditions.”
In the study, eighty-five healthy adults were tasked with suppressing unwanted memories while undergoing functional MRI scans. Half of the participants slept a whole night in a sleep lab before the task, while the others stayed awake throughout the night.
The results showed that those who had slept exhibited more significant activity in the right dorsolateral prefrontal cortex—a brain area that governs thoughts, actions, and emotions—than those who had been awake. Additionally, the well-rested participants displayed decreased activity in the hippocampus—a brain region associated with memory retrieval—during their efforts to suppress unwanted memories.
Among those who slept in the lab, individuals who spent more time in REM sleep demonstrated better engagement of the right dorsolateral prefrontal cortex during memory suppression. This finding underscores the importance of REM sleep in revitalising the brain mechanisms that prevent unwanted memories from surfacing.
Dr Harrington concluded: “Our findings underscore the vital role of sleep in managing our memories and ongoing thoughts effectively.”
More information: Marcus O. Harrington et al, Memory control deficits in the sleep-deprived human brain, Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.2400743122
Journal information: Proceedings of the National Academy of Sciences Provided by University of East Anglia
