Cortisol, the stress hormone produced in emotionally intense situations, can help you remember. But how does it affect the brain?
Experience teaches us that stress, when present in moderate forms, can cement memories of an emotionally intense experience in the brain. But how does he do it?
Scientists at Yale University analyzed the role of cortisol, a hormone produced in response to stressful stimuli, in strengthening memories. Discovering that this substance strengthens emotional memories by changing the functioning and way of communicating of the brain networks involved in emotions and memory. The research was published on Science Advances.
Two separate moments
We have long known that cortisol can strengthen memory, but understanding how this happens is more complex, because it is not clear whether the hormone influences the brain’s responses to highly emotional experiences, or whether it intervenes in the formation of memories (or both).
In fact, to form the memory of an emotionally impactful experience, one must first perceive it as intense, and then encode it in long-term memory. The aim of the study was to examine these two processes separately.
Stress pills
Participants took a hydrocortisone pill (the drug cortisol hormone) or a placebo, and then looked at a series of images while undergoing functional magnetic resonance imaging (fMRI), a technique that measures changes in blood circulation and oxygen levels associated with brain activity.
The volunteers had to report their emotional reactions to each image and, the next day, demonstrate how much they remembered the images they observed. Everyone took the test twice, once under cortisol and once after the placebo, without knowing what they had taken and without the experimenters knowing (a type of condition called double blind).
The scientists sought to understand whether different brain regions showed synchronized activity patterns that could indicate simultaneous participation in the same process. They did this in very short sessions, lasting 5 seconds each, to understand whether the identified brain activity could predict the perceived emotional intensity of visual stimuli and – separately – whether it could predict how well the participants would remember those same images.
The role of cortisol
Thanks to the experiment, the scientists observed that cortisol had indeed improved the participants’ ability to remember emotionally intense experiences and had done so by acting differently on the brain networks responsible for analyzing emotions and forming memories.
In the first case, it increased participants’ involvement, helping their brains respond more promptly to the emotional meaning of an experience.
Cortisol acted on memory networks by making their activity patterns more specialized for emotional information. Furthermore, the hormone helped these two separate systems work together in a more effective way.
This is why stress does not improve memory regardless and indiscriminately, but only for the most emotionally salient events. Which may also suggest a trick to remember better: if you are stressed, thinking about the most stimulating or emotional elements of a situation can help keep them in mind.
