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Published on 25 April in the leading scientific journal Brain, a new study argues that insomnia could primarily be the result of some people‘s failure to gradually transform emotionally unpleasant memories – typically involving embarrassment and other types of failure – into neutral ones.
In the study, authors hailing from the Netherlands Institute for Neuroscience explain that while sound sleep is highly consequential for memory consolidation, what people tend to focus less on is the fact that catching your z‘s is also necessary for getting rid of the distress associated with painful events.
“Sayings like ‘sleeping on it’ to ‘get things off your mind’ reflect our nocturnal digestion of daytime experiences. Brain research now shows that only good sleepers profit from sleep when it comes to shedding emotional tension. The process does not work well in people with insomnia. In fact, their restless nights can even make them feel worse,” said first author Rick Wassing.
The new study, which asked participants to relive their most shameful decades-old experiences while undergoing an MRI scan, might help explain the results of a different study recently published by the same research group.
Overclocked processing of negative memories could be one of the key mechanisms behind insomnia. Image: Alyssa L. Miller via flickr.com, CC BY 2.0
Namely, by asking volunteers to sing karaoke-style with headphones on to prevent effective pitch and tone adjustment, and later replaying the out-of-tune recordings back to the participants, the researchers found that only those who had slept well that night were able to react to those recordings more or less neutrally, i.e., without overwhelming embarrassment, the following day.
These findings could prompt more work on the links between insomnia and brain regions involved in emotional control, rather than focusing exclusively on brain areas responsible for sleep more directly.
“In conclusion, the present study adds to the converging body of evidence that implicate the ACC [anterior cingulate cortex] as an important cortical area in the mechanisms involved in insomnia. Our findings suggest involvement of the dorsal ACC in insufficient long-term adaptation to emotional memory in people suffering from insomnia,” wrote the researchers.
In other words, people with sleep disturbances might be haunted by their past blunders and mistakes, the memory and processing of which is not effectively shut down during the REM stage of sleep.