How is Emotional Memory Consolidated in the Brain?

Science claims that sleep, more specifically, the REM phase, is decisive for consolidating memories with a certain emotional charge in the brain. In fact, memory, emotions, and night rest are intimately related.

Written and verified by the psychologist Valeria Sabater.

Last update: 22 December, 2022

Why are traumatic and highly painful experiences so difficult to forget? Understanding how emotional memory is consolidated in the brain has long been a mystery to scientists. In fact, memories steeped in the full palette of our universe of emotions partly define who we are. It’s a part that the scientific field would like to better understand.

There are various theories that attempt to reveal how we codify and evoke each fact, nuance, situation, and lived experience. Indeed, something that’s inherent about being human is that everything that causes us hope, fear, surprise, sadness, or anguish sticks much more in the memory. It’s as if someone has sculpted it in the depths of our brains.

The smartest and most learned experts in the field of neuroscience claim that, behind this peculiarity, lie the neurotransmitters. They mediate the consolidation of long-term memory and also the emotional content. However, there’s another fascinating element inherent in this storage process.

As a matter of fact, it seems to be sleep that’s the key to the machinery in which emotional memories last forever.

How emotional memory is consolidated in the brain

An investigation conducted by the Huazhong University of Science and Technology (China) claimed that people with insomnia are at increased risk of depression. This coincides with a hypothesis that many neuroscientists have been considering for a long time.

They claim that sleep restriction affects not only our memory but also our emotional well-being. Furthermore, they suggest that patients with chronic sleep disturbances have up to a 90 percent risk of developing major depression. This suggests that a good night’s rest is key not only to establishing memories but also to better regulation of emotions.

The importance of REM sleep in the formation of neutral and emotional memories

The University of Notre Dame (France) conducted research with a group of patients in their sleep unit. They claimed that REM sleep  favors both the processing and consolidation of emotional memory. Somehow, the final stage of sleep articulates the final establishment of this type of information in the brain.

We all know that a good night’s rest is decisive for the proper performance of our brain functions. In those hours of sleep, the brain removes cellular debris so that we maintain healthy cognitive systems. In addition, it favors new neural connections, organizes the information learned, and discards what it considers to be unimportant.

However, it not only manages and establishes neutral memories but also consolidates long-term emotional memories in the hippocampus and in various neocortical areas.

The hippocampus and the amygdala: promoters and guardians of emotions

The understanding of the mechanism of memory has improved remarkably in recent years, thanks to neuroimaging techniques. Indeed, magnetic resonance imaging has made it possible to understand how emotional memories are consolidated in the brain.

Both the hippocampus and the amygdala favor experiences such as trauma, happiness, love, or fear. They then become, (for better or worse) lasting memories. Sleep is the link that fosters and favors their formation.

Both short-wave cycles and those that accompany REM sleep reactivate hippocampal memory traces. This set of waves and their frequencies is decisive for reactivating memories, encoding, and consolidating them. It’s a fascinating process.

The way in which emotional memory is consolidated in the brain depends on the night’s rest

All of the above might pose the question, what would happen if an individual was subjected to sustained sleep deprivation? Would they stop remembering those most intense and emotional experiences? Not quite. What would happen is that their memory, in general, would deteriorate and depressive symptoms would appear. Indeed, a lack of sleep has a great impact on the brain.

It would be interesting to better understand the possible links between chronic sleep disorders and alterations in emotional memory in various psychiatric conditions. In fact, making progress in this respect would allow us to develop more innovative and effective interventions.

Taking care of, attending to, and promoting good sleep hygiene is decisive for our health in general, including psychological health.

Our memories, both the unhappy and the less kind ones, make up who we are. They sculpt us and shape us in a constant process that never stops. Furthermore, they give us the opportunity to shape brighter and kinder experiences that could counteract, for example, childhood traumas.