Does our brain have a button to erase bad memories?

Neuroscience seems to have found some pieces of the puzzle that can help us. Even the smallest factor could play a role in determining whether to save or delete a memory.


Ulysses has not been heard from for years. He could have died in the Trojan War. His daughter, Telemachus, visits Menelaus and his wife, Helena, seeking information about his father. There he attends a banquet in which Menelaus remembers the exploits of the king of Ithaca.

At that moment, the diners fall into a deep sadness when remembering him. But Elena orders the servants to serve nepenthes , the drink of oblivion. “Whoever drinks this drink will calm all his ills and will be incapable of feeling sadness, since it makes him forget painful memories.” It is then when happiness returns to those present.

This is how Homer narrates it in song IV of the Odyssey . But is it that easy to forget a traumatic memory? Is there any scientific evidence to prove it?

Why this facility to remember the bad?

Our memory stores many of the things that happen to us during the day, but much of it ends up being forgotten. However, we have a certain facility for storing bad memories, despite not being a free process: our nervous system needs to modify certain neural circuits, with the consequent protein synthesis and cellular energy expenditure.

It is curious: all this effort to save a memory that will surely leave us psychological sequelae and that, in the worst case, cause us a post-traumatic stress disorder . Why?

Part of the explanation is based on the fact that these negative experiences are strongly associated with emotions. And our brain classifies and stores memories based on their usefulness, considering that those linked to emotions are useful for our survival. If we have been very scared when crossing a dangerous area of ​​our city, the brain stores it so that we do not do it again.

The situation is complicated when the experience is truly traumatic. In this case, our thinking organ tends to hide these experiences, but keeps them raw. As a quick defense mechanism it’s fine. The problem comes when, for whatever reason, the bad memories reappear. So the damage can be very great when dealing with experiences that have been archived without cooking .

Light and sound to eliminate traumatic experiences

Neuroscience seems to have found some pieces of the puzzle that can help us. Even the smallest factor could play an important role in determining whether we save or delete a memory.

For example, light , something so common and that affects us all, also flies ( Droshopila melanogaster ), capable of forgetting traumatic events when kept in the dark. And all thanks to a protein that acts as a modulator of memory and that, and this part interests us, is evolutionarily highly conserved. Or in other words, it is present in all animals, including humans. The explanation may be relatively simple: light acts as a modulator of brain functions, memory maintenance included.

Sounds are another important piece, especially when we sleep. Sleep is essential for memory processing . During the day our brain installs applications (memories) and updates them at night . In this way, the newly acquired memory would be transformed into long-term memory during the night’s rest.

Following this reasoning, we could also do the opposite: use stimuli, in this case auditory, to uninstall negative experiences, as confirmed by researchers from the University of York (England) in a recent study .

Despite the fact that these types of studies are still in the experimental phase, they could be very useful for developing future therapies that allow us to weaken traumatic memories based on auditory stimuli while we sleep.

Promising drugs

Some of you may be wondering if in the future you will sell light pills or sound pills to help us forget bad memories. We do not have the answer, but we do have scientific evidence that some existing drugs could contribute to the erasure of traumatic memory.

Propranolol, for example, a drug used to treat arterial hypertension and which allows experimental animals to forget a learned trauma . The key could lie in a protein in neurons that determines whether memories have to be changed or not. If this protein is degraded, memories become modifiable , and if it is present, they are maintained.

An anti-inflammatory as a shield against intrusive memories

Despite the fact that these are works carried out on experimental animals, they are an excellent model for studying the nervous system. The human brain, while similar, is more complex. Let’s go, then, to him.

Traumatic experiences are very difficult to forget and seriously affect the people who suffer them. Researchers from London University College thought the same thing, who have just published a study describing how hydrocortisone – an anti-inflammatory drug commonly used for the treatment of arthritis – could promote the process of forgetting intrusive memories if administered after an event traumatic.

Interestingly, the effect was different for women and men, depending on the level of sex hormones in their bodies. For example, men with high estrogen levels had fewer traumatic memories. In women, the opposite was true: elevated estrogen levels made them more susceptible to bad memories after hydrocortisone treatment. This shows that the same drug can have opposite effects in some people than in others; hence the importance of research with a gender perspective.

At present, hydrocortisone has only been effective when administered during the hours immediately after the trauma or before sleep, when the memory is consolidated. Nonetheless, science continues to advance in the hope of accelerating the natural process of forgetting and limiting long-term psychological distress.

It is true that this type of study has some limitations, such as the way in which traumatic stimuli are provoked experimentally may not reflect the severity of the memories that occur after a bad experience in real life. Even so, it opens new doors in the study of new treatments for victims of post-traumatic stress. And maybe even the possibility of erasing the bad memories that prevent them from leading a normal life.

We don’t know what will happen in the future, but if you are wondering, we recommend you watch Forget me! (2004). Maybe I’ll find some hint of what’s to come.The Conversation