New Research: REM Sleep Strengthens Emotional Memories

Lisa Franchi December 19, 2012

Past studies have linked sleep with the improved consolidation of memories, particularly the emotionally-charged ones. But for the first time, scientists found it doesn’t just consolidate, but also help retain such memories.

People who experienced rapid eye movement (REM) sleep soon after being presented with scenes that have negative emotional impact had a better memory of the emotional objects as compared to those who didn’t sleep for at least 16 hours – a new study found.

Sleep critical for emotional memory formation

It is a known fact that emotional memories are more easily remembered than non-emotional ones. Also, REM sleep has been repeatedly shown to improve the retention of emotional memories. However, the extent to which it contributes to this improvement is still unknown.

Emotion, as scientists put it, is a double-edged sword that can either enhance or obstruct cognitive functions and behaviours. For instance, an emotionally-charged event, such as hearing a gunshot or witnessing a car wreck can strengthen one’s memory of such event, whereas irrelevant or non-emotional scenes or objects do not (such as the area where the wrecked car was park).

In a study by the University of Notre Dame, researchers found that the sleeping brain preserves the emotionally-charged memories which are crucial for survival. However, there was a diminished memory for the neutral or irrelevant information also involved in the scene.

For their study, the researchers recruited a number of people to undergo a memory test involving emotional objects. Volunteers who slept soon after learning showed a significant improvement in recalling the memory as compared to those whose sleep was delayed for 16 hours.

According to Jessica Payne, one of the researchers and a psychology researcher at the university, their findings suggest that REM sleep helps people selectively preserve only the memories that are essential in emotional processing, as well as to survival.

While previous research suggests that sleep helps consolidate emotional memories, their study was the first to show that REM also helps the brain give more focus on the most emotional part of an event, strengthening our memories of it.

The report was published in the journal Frontiers in Integrative Neuroscience.

Emotion, Memory, and Survival

Life-and-death situations are usually the memories that are etched in our brains. Non-conscious emotional memories make us more alert and cautious, and enable us to recognise potential threats. Because of this, we intelligently respond to a difficult situation and increase our chance of survival.

Dear Readers,

What other methods can help improve quality of sleep to access memories?

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Source of this article:

Sleep promotes lasting changes in selective memory for emotional scenes