How brain suppresses fear

Researchers have found neurons that prevent mice from forming fearful memories in an area of the brain called the hippocampus.

Attila Losonczy, from Columbia University in New York and colleagues, who were interested to find how the hippocampus stores memories of a particular context and then separates this memory from a fearful event, found that these inhibitory neurons ensure that a neutral memory of a context or location is not contaminated by an unpleasant event occurring at the same time, the BBC reported.

According to the team, their work could one day help them better understand the neural basis of conditions such as post traumatic stress disorder.

The team, which looked at individual neurons in the brains of mice, found inhibitory cells- called interneurons- were crucial for fear memory formation to travel to the correct part of the brain.

Losonczy told the publication that these cells are activated by the unpleasant salient event and they act somewhat like a filter. They may function to block out unwanted information related to this strong, salient event.

When mice were conditioned to express fear in a particular context, they later associated the same environment with the unpleasant event.

However, when scientists deactivated these inhibitor neurons, the mice no longer showed any fear.

The study was published in the journal Science.