According to a new study, stress can disrupt the way the brain forms memories, causing people to feel threatened even in safe situations.

Researchers have found that stress creates clusters of neurons in the brain, called engrams, that grow larger, interfering with memory and increasing fear.

This may help explain why people with conditions like PTSD (post-traumatic stress disorder) or anxiety often feel unsafe in harmless environments.

For example, after burning a finger on a hot pan, a person under stress may begin avoiding not only the pan, but the entire kitchen. This generalized fear is common in people struggling with post-traumatic stress disorder (PTSD) or anxiety.

The study published in Cell explored how stress affects memory, focusing on the amygdala, the part of the brain that regulates emotions and stress responses. To understand this process, scientists worked with rats.

How does stress change memory?

In experiments, some rats were made stressed by increasing their stress hormone levels. Afterwards, they were exposed to two sounds: a neutral one and one followed by a mild shock to mimic a frightening event. Stressed rats remembered the difference between the two sounds, they froze only when they heard the sound associated with the shock.

But the stressed rats were surprised by both sounds, which showed that they couldn’t tell the neutral event from the fearful one.

Further tests revealed that stressed rats formed larger engrams, memory bundles, in the brain than their non-stressed counterparts.

Normally, the brain controls engram size using a chemical called GABA, which works like a bouncer in a club, letting only specific neurons in. But under stress, this mechanism fails, causing more neurons to accumulate in the engram, distorting the memory.

possibility of treatment

The researchers found that two drugs, including mifepristone, could reverse this effect in stressed rats by blocking stress pathways in the brain.

However, these drugs only work during memory formation and have other side effects, making them an unlikely treatment for humans.

Scientists are now exploring whether memories can be adjusted after they are formed, potentially opening new doors to helping people affected by stress-related memory problems.