According to the American Medical Association and the American Bar Association, death is legally defined as the "irreversible cessation of all functions of the entire brain, including the brain stem." So how, then, do we explain the fact that up to 20 percent of those who die and then are brought back to life report that they retained consciousness even during the near-death experience? How do we explain the common phenomenon of seeing the black tunnel with the light at the end and the gathered dead relatives? Is consciousness a function of the seemingly inert brain, or does it reside somewhere outside of the "vital functions of the organism"?
For many years, scientists have been trying to resolve these questions through research into the physiology of near-death experiences (NDEs). While some attribute the reports of NDEs to the overly active imaginations of the subjects or to mystical origins, most in the medical establishment believe the experiences can be explained by simple physiology. These theories typically center on the idea that physiological changes occur in the brain as it begins to shut down -- only to reverse before actual death. For instance, a 2006 study published in the journal Neurology concluded that the near-death experience is most likely the result of an "REM intrusion" into waking consciousness. In other words, the experience is akin to moving to the zone we occupy between the sleeping and waking states, where aspects of the REM-sleep state spill over into awareness.
Other researchers have asserted that the system emits certain psychoactive chemicals upon death, and that these bring about the NDE "symptoms." Dr. Richard Strassman of the University of New Mexico, School of Medicine, for instance, contends that the pineal gland releases the chemical Dimethyltryptamine (DMT), which brings on hallucinations, though he wasn't able to reproduce the effect in most of his test subjects when he administered DMT to them. But then again, lack of evidence should never get in the way of a good theory. Another expert, Dr. Birk Engmann, argues that the near-death experience is simply the manifestation of psychopathological symptoms triggered by brain malfunction, which comes about because of the lack of blood supply to the brain. And Dr. Gerald Woerlee, an Australian researcher, says that experiences of waking consciousness during the NDE actually are the result of the patient being jolted back into consciousness for a few seconds. He does agree that the experience changes the brains of NDE survivors, but his perspective differs dramatically from that of those who believe there's a spiritual explanation.
"The brain function of many of these people who have undergone a near-death experience is altered," Woerlee says. "That's correct. It is altered. Extreme oxygen starvation does change brain function -- because it causes brain damage to the larger cells in the brain."
All of these theories presuppose that though the brain is shutting down -- although it's undergoing physiological changes -- it still has some viability, that it still functions at some level. But new research flushes this idea down the toilet, because at least one subject retained total recall of what happened to her on the operating table when she had absolutely zero measurable brain activity.
According to a report on National Public Radio, the subject, music producer Pam Reynold, "died" of a brain aneurysm, and the only way to save her was to perform an outrageously risky surgery. The physicians chilled her body and then "drained the blood out of her head like oil from a car engine." According to her physician, Dr. Robert Spetzler, she was "as deeply comatose as you can be and still be alive."
In spite of the fact that her brain was completely drained and non-functional (she was effectively brain dead for the entire operation), Ms. Reynold says she "floated to the ceiling" and witnessed 20 people working on her in surgery. Later, she was able to describe, in detail, the surgical instruments used during her operation and comments made by the medical team. Oh by the way, she was able to observe this even though her ears and eyes were covered with impenetrable barriers -- in addition to being brain dead. And, of course, she also had the typical near-death experience of seeing a tunnel with bright light and long-dead relatives.
When Ms. Reynold reported her after-death experience to Dr. Spetzler, he was startled. "From a scientific perspective," he says, "I have absolutely no explanation about how it could have happened."
Neuroscientist Mario Beauregard of the University of Montreal, on the other hand, does have a theory based on his recent study of 15 people who had near-death experiences that might offer an explanation. Dr. Beauregard contends that the mind lives outside the physiology of the brain, so that even when the brain dies, the mind (as opposed to the brain) has the ability to remain aware. In his study, he asked subjects to recall what happened to them when they died as he measured their brain-wave activity via 32 electrodes. According to his findings, the NDE changes brain wave patterns permanently, conferring the individual with an ability to move into a delta state similar to that experienced by monks, yogis, and long-time meditators. And Dr. Beauregard says, "...the near-death experience triggers something at a neural level in the brain. And perhaps this change, in terms of brain activity, is sort of permanent." Taking his ideas to the next step, this would mean that the mind alters the brain.
Does Ms. Reynold's experience mean that there's life after death, that the "mind" survives the body? Not necessarily. All it means is that all of the "scientific" explanations for the NDE phenomenon proffered so far don't hold up, that we have no rational explanation at all for reports of consciousness after death. We do know from existing research that most people who come back from dying have a greater capacity to deal with stress, that many report feeling spiritually awakened by the experience, and that a significant number report nearly identical experiences of seeing light, meeting deceased dear ones, and of observing and hearing things they shouldn't have been able to perceive given that they were dead. But everything science thought true about death being defined by the absence of brain activity is thrown into question -- as is the advisability, I must say, of harvesting organs when brain activity ceases. Based on this new evidence, the implications of what brain dead-people might be experiencing when their organs are removed, as Hamlet said, "Must give us pause."
P.S. A new large-scale scientific study of the near-death experience was launched this past year. The study, headed by Dr. Sam Parnia and colleagues at the Cornell Medical Center, is a three-year project involving 25 major medical centers and 1500 patients who survived cardiac arrest. Stay tuned!