Are near-death experiences purely physical, or do they provide a glimpse into a mystical realm beyond ordinary awareness?
The June 2020 issue of Scientific American has an article by Christof Koch that delves into this question. "Tales of the Dying Brain" is well worth a read regardless of how you look upon near-death experiences.
Koch makes clear his basic stance on this subject, one that I heartily agree with.
I accept the reality of these intensely felt experiences.
They are as authentic as any other subjective feeling or perception. As a scientist, however, I operate under the hypothesis that all our thoughts, memories, percepts and experiences are an ineluctable consequence of the natural causal powers of our brain rather than of any supernatural ones.
That premise has served science and its handmaiden, technology, extremely well over the past few centuries. Unless there is extraordinary, compelling, objective evidence to the contrary, I see no reason to abandon this assumption.
Koch then acknowledges the power a near-death experience can have for the person who comes close to dying.
The challenge, then, is to explain NDEs within a natural framework.
As a long-time student of the mind-body problem, I care about NDEs because they constitute a rare variety of human consciousness and because of the remarkable fact that an event lasting well under an hour in objective time leaves a permanent transformation in its wake, a Pauline conversion on the road to Damascus — no more fear of death, a detachment from material possessions and an orientation toward the greater good. Or, as in the case of Hemingway, an obsession with risk and death.
Psychedelic experiences bear a resemblance to NDEs.
Similar mystical experiences are commonly reported when ingesting psychoactive substances from a class of hallucinogens linked to the neurotransmitter serotonin, including psilocybin (the active ingredient in magic mushrooms), LSD, DMT (aka the Spirit Molecule), and 5-MeO-DMT (aka the God Molecule), consumed as part of religious, spiritual or recreational practices.
There's still a lot to learn about near-death experiences. However, Koch makes a case for how they should be viewed.
Modern death requires irreversible loss of brain function. When the brain is starved of blood flow (ischemia) and oxygen (anoxia), the patient faints in a fraction of a minute and his or her electroencephalogram, or EEG, becomes isoelectric — in other words, flat. This implies that large-scale, spatially distributed electrical activity within the cortex, the outermost layer of the brain, has broken down.
Like a town that loses power one neighborhood at a time, local regions of the brain go offline one after another. The mind, whose substrate is whichever neurons remain capable of generating electrical activity, does what it always does: it tells a story shaped by the person’s experience, memory and cultural expectations.
Given these power outages, this experience may produce the rather strange and idiosyncratic stories that make up the corpus of NDE reports. To the person undergoing it, an NDE is as real as anything the mind produces during normal waking. When the entire brain has shut down because of complete power loss, the mind is extinguished, along with consciousness. If and when oxygen and blood flow are restored, the brain boots up and the narrative flow of experience resumes.
This is how Koch concludes his piece.
More than 150 years later neurosurgeons are able to induce such ecstatic feelings by electrically stimulating part of the cortex called the insula in epileptic patients who have electrodes implanted in their brain. This procedure can help locate the origin of the seizures for possible surgical removal. Patients report bliss, enhanced well-being, and heightened self-awareness or perception of the external world.
Exciting the gray matter elsewhere can trigger out-of-body experiences or visual hallucinations. This brute link between abnormal activity patterns — whether induced by the spontaneous disease process or controlled by a surgeon’s electrode — and subjective experience provides support for a biological, not spiritual, origin. The same is likely to be true for NDEs.
Why the mind should experience the struggle to sustain its operations in the face of loss of blood flow and oxygen as positive and blissful rather than as panic-inducing remains mysterious.
It is intriguing, though, that the outer limit of the spectrum of human experience encompasses other occasions in which reduced oxygen causes pleasurable feelings of jauntiness, light-headedness and heightened arousal — deep-water diving, high-altitude climbing, flying, the choking or fainting game, and sexual asphyxiation.
Perhaps such ecstatic experiences are common to many forms of death as long as the mind remains lucid and is not dulled by opiates or other drugs given to alleviate pain. The mind, chained to a dying body, visits its own private version of heaven or hell before entering Hamlet’s “undiscovered country from whose bourn no traveler returns.”