A group of passengers who were convinced they were going to die when their plane lost power over the Atlantic Ocean in 2001 have had their brains scanned while recalling the experience. It sounds pretty brutal, but the results are providing important insight into how our brains process and store traumatic memories, and could help scientists to better understand post-traumatic stress disorder (PTSD).

The passengers were on board Air Transat Flight 236, which suffered a fuel leak and was forced to make an emergency crash landing on a small island military base in the Azores - but not before first dropping tens of thousands of metres in the space of a few minutes.

Published in Clinical Psychological Science, this is believed to be the first study to look at eight individuals who all experienced the same trauma at once, and the researchers found that all of the survivors had incredibly detailed memories of the event.

"This traumatic incident still haunts passengers regardless of whether they have PTSD or not," lead author Daniela Palombo from Baycrest Health Science in Canada said in a press release. "They remember the event as though it happened yesterday, when in fact it happened almost a decade ago [the scans were conducted in 2011]. Other more mundane experiences tend to fade with the passage of time, but trauma leaves a lasting memory trace."

"We've uncovered some hints into the brain mechanisms through which this may occur," she added.

The researchers asked eight of the survivors to watch news footage of their near-crash and tell them about the event from inside a function magnetic resonance imaging (fMRI) scanner. They also showed them footage from the 9/11 attacks and a neutral event to see how their brains responded.

They found that while the patients reflected on their own traumatic experience, a network of brain regions known to be involved in emotional memory lit up - including the amygdala, hippocampus and midline frontal and posterior regions. This didn't happen when they were talking about the neutral events.

94165 webDaniela Palombo

But the team was surprised to find that a remarkably similar network of brain regions was activated when the survivors recalled the less personal trauma of 9/11, which happened just three weeks after their crash landing on board the Air Transat flight.

The researchers then tested people who hadn't experienced a personal trauma with the same 9/11 footage, but found that their brains didn't have the same response.

The team believes that this could be the result of a 'carryover effect' of their nightmare flight, suggesting that it changed the way those affected view the world. "[The results] may indicate that the Air Transat flight scare changed the way the passengers process new information, possibly making them more sensitive to other negative life experiences," they explain.

This type of data is pretty exciting for scientists, who normally have to rely on animal model studies, and is a big step towards understanding how trauma changes us.

"Here we have a group of people who all experienced the same extremely intense trauma. Some were more affected and went on to develop PTSD; some did not," said Palombo. "How each of them responded to this terrifying event has been informative for helping us move a step closer toward understanding the brain processes involved in traumatic memory."

We have nothing but respect for anyone who can go through a near-death experience and then relive it for science. Thank you.