Why your brain dwells on negative memories as you sleep

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  • Brain is hardwired to dwell on negative memories that strengthen during sleep
  • Human beings have the capacity to strengthen weak memories using emotions
  • Those who had been to bed remembered more negative emotional scenes 
  • Researchers have said this points to the adaptive nature of human memory

Tim Collins For Mailonline

If you go to bed angry about something those negative memories will be even harder to reverse the next day, researchers have found.  

Experts have found that the brain is hardwired to linger over negative memories, strengthening them while we sleep.

Previous studies suggest that emotions, sounds and other stimuli that are associated by the mind with particular events can help to improve our recollections of them.

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If you go to bed angry about something those negative memories will be even harder to reverse the next day, researchers have found (stock image)

If you go to bed angry about something those negative memories will be even harder to reverse the next day, researchers have found (stock image)

If you go to bed angry about something those negative memories will be even harder to reverse the next day, researchers have found (stock image)

EMOTIONS AND MEMORY

Given new and relevant information, human beings have the capacity to strengthen weak memories using emotions.

Researchers have said this points to the adaptive nature of human memory.

One 2015 study focused on how our brains remember emotionally arousing stimuli, such as evocative imagery or traumatic events. 

In particular, the study has looked into how the September 11 terrorist attacks in the the US affect memory retention.

They found that emotion increases our ability to remember by affecting activity in brain regions involved in emotional processing.

The amygdala and striatum, as well as the regions involved in encoding new experiences, like the hippocampus, were particularly affected.

Emotion also increases the strength of our memory over time – a process called consolidation.

Strong emotion can strengthen memory for positive events, such as a surprise birthday party thrown by close friends, and for negative events, such as making an embarrassing faux pas at the office holiday party.

Researchers at Beth Israel Deaconess Medical Centre in Boston put this to the test with a group of 57 volunteers. 

They were shown a series of separate images in each eye, with one depicting a neutral scene and another an unpleasant one.

Because each eye is linked to a separate half of the brain, the mind is able to process the emotional impact independently.

Emotional scenes that evoked a negative reaction were ‘localised’ in one hemisphere, researchers found from looking at the electrical activity of the brain.   

Participants were then asked to recall the images 12 hours later, with half of the group having slept in that time.

Those who had been to bed remembered more negative emotional scenes than their counterparts who had stayed awake.

This second group was able to recall an approximately equal number of negative and neutral images.

Speaking to The Times, Roy Cox, a research fellow at the centre and the study’s lead author, said: ‘This would provide an explanation of how sleep selectively stabilises emotional memories.’ 

The findings, which haven’t been peer reviewed, are due to be presented at the Neuroscience 2017 conference, being held today in Washington.

Given new and relevant information, human beings have the capacity to strengthen weak memories using emotions.

Researchers have said this points to the adaptive nature of human memory. 

One 2015 study focused on how our brains remember emotionally arousing stimuli, such as evocative imagery or traumatic events. 

In particular, the study has looked into how the September 11 terrorist attacks in the the US affect memory retention.

They found that emotion increases our ability to remember by affecting activity in brain regions involved in emotional processing.

A group of 57 volunteers was shown imagery depicting negative and neutral emotional scenes before being asked to recall them 12 hours later. Those who had slept remembered more negative images compared to those who stayed awake (stock image)

A group of 57 volunteers was shown imagery depicting negative and neutral emotional scenes before being asked to recall them 12 hours later. Those who had slept remembered more negative images compared to those who stayed awake (stock image)

A group of 57 volunteers was shown imagery depicting negative and neutral emotional scenes before being asked to recall them 12 hours later. Those who had slept remembered more negative images compared to those who stayed awake (stock image)

The amygdala and striatum, as well as the regions involved in encoding new experiences, like the hippocampus, were particularly affected.

Emotion also increases the strength of our memory over time – a process called consolidation.

Strong emotion can strengthen memory for positive events, such as a surprise birthday party thrown by close friends.

It also apples to negative events, such as making an embarrassing faux pas at the office holiday party.