A sleepless night doesn’t just leave you tired—it may also make it harder to control unwanted memories, a recent study about sleep’s role in emotional memory has found.
How Rest Affects Our Ability to Forget
Using functional magnetic resonance imaging, researchers studied brain activity in 85 healthy adults divided into two groups: those who had a restful night’s sleep and those who stayed awake all night.Participants were shown faces paired with various scenes, including emotionally negative images such as car crashes or fights. The people were then asked to either recall the associated scene or suppress the memory.
“The participants who were sleep deprived were unable to engage the area of the brain that helps us suppress unwanted memories,” Cairney said. “Consequently, they could not quash memory related processes in the hippocampus that give rise to intrusive thoughts.”
Well-rested participants, however, showed increased activation in the right dorsolateral prefrontal cortex—a brain region responsible for controlling thoughts, actions, and emotions—compared to sleep-deprived individuals. They also had reduced activity in the hippocampus, which is involved in memory retrieval.
REM Sleep Key to Memory Suppression
Participants who experienced more REM sleep, the stage during which most vivid dreams occur, demonstrated a better ability to engage the right dorsolateral prefrontal cortex during memory suppression. This suggests that REM sleep helps restore the brain’s ability to control unwanted memories.“This is really important to our understanding of mental health issues as it is well documented that those who suffer with anxiety, depression, or PTSD also have difficulty with sleep,” Cairney said.
“Now that we have [a] better understanding of the mechanisms in the brain that can help restrict negative memories and thoughts, we can perhaps work on more targeted treatments and behavioral therapies that assist with improving sleep.”
The study authors emphasized that their findings contribute to mounting evidence about how sleep deprivation affects the ability to regulate thoughts and actions.
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