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“Never go to bed on an argument," so the saying goes. And according to a new study, we should take note of this age-old advice. Researchers have found that going to sleep while still holding on to negative memories can make it harder to suppress them.
In the recent years, neuroscientists have learned how important sleep is for learning and memory.
A study reported by Medical News Today uncovered evidence that rapid eye movement (REM) sleep – the cycle of sleep in which dreams occur – is essential for memory consolidation, the process by which information is transferred from short-term to long-term memory.
On the other hand, there are certain memories which we would rather not hold on to, for instance, a traumatic event. Studies suggest that we are able to voluntarily suppress them to some extent in order to cope with trauma.
"A failure to suppress unwanted memories has been linked to symptoms in a number of psychiatric disorders including the ruminative state found in depression and intrusive memories in post-traumatic stress disorder (PTSD)," note Liu and colleagues.
Overtime, emotional memories can become increasingly resistant to suppression, which they speculate is down to memory consolidation during sleep. However, the cause is still unknown how consolidation impacts the effectiveness of voluntary suppression of unwanted emotional memories.
Liu and colleagues enrolled 73 male college students and asked them to take part in a number of memory suppression tasks over 2 days.
Subjects were tasked to learn associations between faces and aversive images, so that when they were reintroduced to each face, memories of the aversive image would arise. They were presented with the faces again, both 30 minutes and 24 hours after learning the associations and told to suppress any negative memories that came to mind.
In this experiment, namely the “Think/No Think” task, participants’ brain activity was monitored using functional magnetic resonance imaging (fMRI).
Results revealed that when participants were presented with the faces 24 hours after the learning task, after having had a good night’s sleep in between, subjects were more likely to remember the aversive images than when they were presented with the faces 30 minutes after the learning task.
Neural circuits were involved in memory suppression 30 minutes after the learning task, were more active in the hippocampus (brain region linked to learning and memory), while 24 hours after, this activity became widely distributed in the cortex, making bad memories harder to repress.
The authors explain:
“Our findings point towards a neurobiological model through which overnight consolidation assimilates aversive memories into more distributed neocortical representations, and makes these memories more resistant to suppression through the prefrontal-hippocampal inhibitory pathway. Our study underlines the importance of memory consolidation in understanding the resistance to suppression of emotional memories, which is a cardinal feature of affective disorders.”
They also added that such information on how brain changes impact memory suppression could give physicians a better understanding of PTSD.
In summary, Liu and colleague believe there is some substance to the theory that one should not go to bed on an argument.
To read the full article, please click on link below.
Category(s):Depression, Post Traumatic Stress Disorder (PTSD) / Trauma / Complex PTSD
Source material from Medical News Today
