The New Science of the Near-Death Experience

In the 1960s, during filming Cleopatraactress Elizabeth Taylor developed a case of pneumonia so severe that she fell into a coma and was pronounced dead by doctors, according to her own account on The Oprah Winfrey Show. While Taylor was in an unresponsive state, she apparently had a near-death experience. She remembers seeing the doctors working on her in the operating room and saying they thought they had “lost” her. She recalls a brief reunion with her ex-husband and producer Mike Todd, who died a few years earlier. She remembered Todd telling her it wasn’t his time yet. When she finally recovered from the coma and pneumonia, she had lost her fear of death, she told Winfrey.

Taylor’s experience has some of the classic characteristics of a near-death experience, or NDE, a term first coined in 1975 by psychiatrist, philosopher and researcher Rick Moody, who experienced one himself. There are hundreds of such stories in the scientific literature today, and yet they remain among the most mysterious phenomena known to neuroscience. This is partly because much of what scientists know about them comes from survivors’ subjective self-assessments long after the experiment ended. But as the science of resuscitation improves, more people survive life-threatening events, such as comas and cardiac arrest, changing the tools we have to plumb their depths.

A Belgian researcher, Charlotte Martial, from the University of Liège, recently made the first EEG recordings of patients experiencing near-death experiences and helped develop a neurophysiological model that she believes can explain how these experiences arise and why they may have evolved. I spoke with Martial, who has studied near-death experiences for more than a decade, about how NDE memories evolve over time, the possible adaptive value of NDEs for humans, and the mysteries that remain.

What is the definition of near death experience?

There is still no universally accepted definition in research. But I like to define the phenomenon as an episode of disconnected consciousness, a mental experience that has no connection to the person’s surroundings or surroundings, but with prototypical characteristics such as out-of-body experience, encountering entities, seeing bright light, and an intense feeling of peace. And this happens when we are close to death or when we believe we are close to death.

Do near-death experiences challenge traditional models of consciousness?

My personal view is that they don’t challenge what we know about physiology. My team took two years to review all the literature on consciousness, everything related to near-death experiences, the dying brain, and created the first comprehensive model that brings together psychological, but also neurophysiological, data to convincingly explain how this complex and intense experience arises during a severe physiological crisis. But we need to empirically test several parts of the hypothesis.

Historically, NDEs have been used to illustrate that we do not understand what happens when we are close to death. This is partly true: many questions remain about what we experience subjectively when we are close to death. But we also have answers. According to our model, when we are close to death, the brain is deprived of oxygen, which creates a lack of energy in brain cells, triggering a chain reaction of several neurochemical mechanisms, including the massive release of specific neurotransmitters like norepinephrine and serotonin. This release of neurotransmitters occurs in specific parts of the brain, such as the parietal and occipital temporal regions, which we have shown to be much more active during this physiological crisis, and which are specifically associated with consciousness, perception and memory.

This demonstrates that we do not need our entire brain to be conscious. We just need specific parts of the brain to be functionally activated, allowing this rich experience to occur.

You have suggested that NDE serves an adaptive function in extreme situations such as threat or collapse. Can you tell me more about this?

We suggest that something called thanatosis, where animals pretend to be dead to protect themselves from predators, may have been a kind of precursor in evolution. With the evolution of the complex brain and language in humans, this stereotyped behavior evolved into a more complex and multidimensional experience that is NDE. Basically, we suggest that NDE is a defense mechanism for coping with a life-threatening situation. This allows the person to disconnect from the surroundings, the surroundings, to become absorbed in a more peaceful mental experience.

Read more: “The afterlife is in our heads”

Wouldn’t such a disconnect make it more difficult to escape a life-threatening situation?

We suggest that this is like a biological reflex that appears in the brain when we are close to death. We also suggest that NDEs may, at least for some, have psychological benefits. Many people who experience an NDE say it transforms their lives. This allows them to evolve and change their own behavior or beliefs.

But would there be situations where it wouldn’t be as adaptive? Suppose you were in an avalanche and needed to escape: wouldn’t you need to be aware and find solutions?

We suggest that NDE occurs when you have no other form of escape. So there is this fight or flight mechanism, but when neither fight nor flight is possible, this alternative would present itself.

What about people who have negative near-death experiences: how do these fit with evolutionary explanations?

Yes, usually we talk about positive near-death experiences, but there are also very distressing ones, where people find themselves in a hellish world, with fire and monsters everywhere. Then we can see that these patients may suffer from PTSD [post-traumatic stress disorder]. This is one of the most intriguing experiments, so far little studied. There are less than 10 scientific articles on this subject. We are still thinking about this in the context of the evolutionary hypothesis.

There are at least two possible explanations. First, maybe a neurotransmitter can explain some of it. So perhaps these patients aren’t experiencing the massive release of endorphins, which trigger intense feelings of peace and calm. And second, people who have had a negative NDE are more likely to attempt suicide than those who have had a positive NDE. This may reflect the state of mind of these people when the life-threatening situation occurred.

Based on what you’ve discovered in your studies, does it appear that some people are more susceptible to near-death experiences than others?

So far, what we are observing in my study, but also in the work of other researchers, is that at least one trait appears to be consistent in patients who report NDEs, namely a propensity for dissociation in daily life. These are not pathological states of dissociation, such as those seen in PTSD or borderline personality disorder, but rather an ability to be connected to internal states and disconnected from the environment.

You recently made the first EEG recordings of people having near-death experiences. What did you find?

It’s not published yet, but we did a two-year prospective study in a hospital where as soon as the patient was transferred to the intensive care unit of our hospital, we ran to hook them up to the EEG, or electroencephalogram. We followed 180 patients, and among them, 12 had near-death experiences. Our preliminary results suggest that the brains of patients who had near-death experiences showed greater complexity than those of those who had not. [Brain complexity is a marker of the brain’s ability to adapt, process information, and maintain integrated, flexible, and efficient neuronal network activity.]

When we are unconscious, such as in a coma or dreaming, measures of brain complexity tend to be very low, well below what they are when we are conscious and awake. When you take a psychedelic, the complexity of your brain is much higher than when you are awake. But unconscious patients who later report NDEs have higher brain complexity than awake patients.

What mystery about near-death experiences would you most like to solve?

Some characteristics of NDEs are still difficult to explain, such as precognition. Some people seem to be reporting future events that will later be confirmed. But so far this has not been properly tested. There is also a big question about the temporality of experience. Our hypothesis is that NDEs occur just before or just after cardiac arrest, where a peak in activity can be observed. This is something that was observed in a study of rats in cardiac arrest. But it is not very clear when the NDE occurs.

It is also unclear how NDE memories evolve. Approximately 98% of the empirical literature in the field is retrospective, meaning that most studies are performed on patients who experienced an NDE years or decades earlier. There are only a few studies that are carried out in real time, like the one we carried out. Again, we haven’t published this study yet, but what we observed is that as early as several days after the acute and severe attack, we can see a change in memory in terms of the content of the experience, which challenges what has been found in the retrospective literature.

Certain traits appeared, others disappeared from their memories. For example, you may have someone who doesn’t report an out-of-body experience upon waking up, but two months later the person reports it.

This is a new discovery, but isn’t it surprising, because we know that human memory is malleable. It makes sense that memory takes some time to be properly encoded in people who have gone through a severe physiological crisis, where sensory input and output are disrupted.

Is it fair to say that some of the content of the near-death experience is a kind of illusion?

It depends on how you define illusion. When you encounter entities or feel like you are leaving your body, these are non-ordinary states of consciousness caused by disturbed perception. So you don’t actually meet your father in a tunnel of light, for example. But near-death experiences are real in the sense that the person who reported them had this vivid and intense subjective experience.

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