What your brain looks like after a near-death experience
June 29, 2015
On August 24, 2001, Air Transat Flight 236, with 306 passengers and crew members aboard, began its scheduled flight from Toronto to Lisbon, Portugal, but didn’t quite make it. Midway over the Atlantic Ocean, there was a fuel leak, then a power outage, and Captain Robert Piché and First Officer Dirk de Jager decided to make an emergency landing. The lights went off, the engines failed, cabin depressurization began, and passengers were given instructions for the deployment of life jackets and oxygen masks.
But just after announcing the plane was about to go into the water, Piché spotted a runway in the Azores, the volcanic islands about 900 miles off the coast of Portugal. To lose altitude, he conducted one 360-degree turn and additional S-turns. Passengers screamed as the plane swung around, then back and forth, but outside their windows they saw water turn to land. Warning his passengers to brace themselves, Piché then aimed for the landing strip, and the plane hit it twice before the crew could apply maximum braking pressure and bring the 200-ton aircraft to a stop. Miraculously, nobody died.
In the years since, the survivors of that near-death experience have become a sort of lab experiment for researchers trying to understand the long-term consequences of post-traumatic stress disorder (PTSD). The person who proposed studying these survivors was Dr. Margaret McKinnon, an associate professor of psychiatry and neuroscience at McMaster University in Ontario, Canada, and one of the passengers on Flight 236. She developed PTSD after that harrowing landing.
“The study was an opportunity to turn something negative into a positive experience and hopefully make a contribution to the science of PTSD,” she says.
In an initial experiment conducted three years after the traumatic incident, 15 passenger-participants—seven with PTSD—completed a memory test to probe the quality of their memories of the flight. “Everyone on board had a different experience,” says McKinnon. Uncomfortable discussing the details of her trauma from that day, she just says, “I thought I would die and came to some form of acceptance around that.”
For the study, participants also were asked to recall two other events: their memories of the events of 9/11 and a neutral autobiographical event. These two other memories would serve as comparison points and help the researchers understand how trauma affects memory.
“There were two main findings from that study,” says Brian Levine a professor of psychology at the University of Toronto and one of the researchers on the project. First, all the passengers remembered a remarkably large amount of detail from the Air Transat incident. Levine refers to this as emotionally enhanced memory. “Everyone on the plane generated two to three times more information about that event than other events we tested,” he says.
The second finding was that the people with PTSD tended to veer off-topic when interviewed about the near-crash, recalling additional but somewhat irrelevant information, compared with the people without PTSD. This suggests they have problems with their control over memory, says Levine. Interestingly, those with PTSD not only remembered more external, tangential details from the traumatic plane landing; their recollections of 9/11 and the neutral event were also cluttered with superfluous details.
Nearly a decade following this initial stage of research, eight passengers agreed to return for a second chapter of the study. This group, which had a brain scan, ranged in age from 30s to 60s and included some who had been diagnosed with PTSD. Placed inside a functional MRI scanner, the eight passengers recalled details of their experience on Flight 236 while they watched the Discovery Channel’s video re-creation of the incident, which included looking down on the island where the emergency landing took place.
“I can tell you, I re-experienced the event, it was that evocative of the experience,” says McKinnon, who participated in the study. “I felt I was suspended in the air again.”
She adds, “They say in trauma the body keeps the score,” and the study’s results provide a neurological explanation why: As the participants recalled their near-plane crash experience, emotional memory regions of their brains lit up—the amygdala, hippocampus and midline frontal and posterior regions.
“Memory is an activation of a number of brain regions at once,” says Daniela Palombo, lead author of the study and a postdoctoral researcher at the Boston University School of Medicine. “The amygdala is classically involved in emotion, while the hippocampus is important to memory. The posterior regions play a role in visual imagery, and the prefrontal cortex comes onboard for self-referential processes.”
Following their latest Flight 236 re-creations, the passengers were asked to recall their experience of 9/11 while watching footage of the terrorist attacks, and, finally, they recalled a neutral autobiographical event. The participants’ brain activity when discussing 9/11 was similar to what had occurred during their memories of the near-plane crash. And, as expected, the pattern did not occur when they recalled a neutral event. What was surprising, though, is that these patterns were not evident in people who hadn't been involved in a near-plane crash, even when they recalled 9/11 while undergoing a brain scan.
“People who have observed trauma might see the world differently,” says Palombo. She believes the emergency landing scare may have changed the way the brains of those passengers process new information. Following trauma, we may be more sensitive to painful life experiences, Palombo suggests, and so we view the world through new lenses. “The research supports the idea of a lasting memory trace, a carryover effect,” she says.
Those passengers would be more affected by 9/11 because, Palombo says, it “hits home—certainly we can imagine they would relate to 9/11 differently than other people.” And PTSD research supports the idea that any element resembling the traumatic event will be perceived by a trauma survivor as threatening, even when it occurs in a safe environment.
The two studies also suggest that how you see the world to begin with may make you more or less predisposed to PTSD, should you undergo a traumatic experience. “Everybody’s memory works differently,” explains Levine. Some people remember events in a precise way, with relevant details lining up in an orderly fashion, while other people seem to take in more superfluous details in a more disorganized way.
“For people who have that second kind of memory, more extraneous information getting in, they may be more susceptible to PTSD when traumatized,” Levine speculates. “It’s the interplay between the cognitive systems and the emotional systems that may determine how you cope.” In those who develop PTSD, “the emotional part may overwhelm the system,” he says.
These findings add fuel to the theory that when it comes to PTSD, it’s not so much that a traumatic memory exists but that it can be later triggered in unpredictable ways and unexpected times. McKinnon’s hope is that an enriched knowledge of brain activity following a traumatic experience could help advance current therapies built around processing these uncontrolled memories.