Mar 25, 2022
The Brain as It Lay Dying
Science reveals that a flash of brain waves occurs at the point of (and even after) death; what can that tell us about life?
Science cannot tell us when the moment of death occurs. Despite all of our technology and all of our research, we still have only a legal definition of death — not a medical or scientific one. Why? Those ephemeral moments between being a living thing and a collection of inanimate materials cannot be measured, and it’s hard to agree on the unusual data that remains. Does the brain die all at once? How much of it must die before it’s really dead? And what if — in some bizarre way — thoughts persist after the brain itself has shut down?
In February of 2022, in the midst of Russian airstrikes against Ukraine and resurgent cases of Covid variants across Europe, an unusual case study gave us the clearest window yet on the dying human brain.
An 87-year-old patient started to have seizures after surgery, so doctors used electroencephalography (EEG) to keep track of his condition. He died shortly after, and is the first human being to have their death recorded in real time. We have, in essence, a recording of his dying moments.
“We measured 900 seconds of brain activity around the time of death and set a specific focus to investigate what happened in the 30 seconds before and after the heart stopped beating,” said Ajmal Zemmar, a neurosurgeon at the University of Louisville. In a paper for Frontiers in Aging Neuroscience, he explained that, “Just before and after the heart stopped working, we saw changes in a specific band of neural oscillations, so-called gamma oscillations, but also in others such as delta, theta, alpha, and beta oscillations.” In essence, the brain had a surge of advanced cognitive activity: It sped up rather than slowing down, like the flash of a candle before going out.
What can these oscillations tell us about the brain as it dies? We know from previous brain research that the neural oscillations measured here are involved in things like dreaming, meditation, memory retrieval, and even flashbacks, where the memories are so intense the patient “dissociates” and feels as if they are back at the time of the event. Zemmar described the patient’s dying brain activity as similar to just such life-recall, suggesting that this might explain near-death experience (NDE), where patients report feeling outside their bodies, seeing past events, or having a sense of moving toward a light.
And yet, for many, the commonality of near-death experiences have served as proof of something more. NDE are triggered during life-threatening episodes when the body is injured. Thousands of survivors talk about leaving their damaged bodies, going to “a realm beyond everyday existence” and being out of space and time. Many see these as mystical experiences, with religious overtones — some even suggest it is proof of life after death. Does this new evidence of the brain’s activity in a dying patient at last answer the questions about where life begins and ends, and even explain away the out-of-body sensations, the sense of peace, the march toward the light?
Christof Koch, writing for Scientific American, reminds us that “NDEs have been with us at all times in all cultures and in all people, young and old, devout and skeptical,” but 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.” He provides numerous examples, from 18th-century naval officers to surgery survivors in the 20th and 21st centuries — all report a similar phenomenon, and suggest the experience is somehow “realer than real.” He accounts for this by describing the way a brain, starved of oxygen and near death, shuts itself down region by region — and suggests that the remaining portions do what they can with power remaining by telling stories.
The new information from this singular case study doesn’t wholly contradict this, but instead reveals that there seems to be a surge of activity after we might expect the brain to have already powered out. As reported, “spectral analysis revealed a surge in absolute gamma power after suppression of neuronal activity in both hemispheres” before ultimately declining and ceasing altogether. This activity does not save the brain from death. So why have we have this interplay between neuronal frequencies as we lay dying? What evolutionary principle does it serve?
According to Zemmar, the brain remained somehow both active and coordinated even after death and may “ be programmed to orchestrate the whole ordeal.” And this raises some unusual questions not only about when exactly life ends (already very muddy waters) but also about why our mind-life ends in the way that it does.
It might help grieving families to know that a loved one was playing the nicest memories at the end, and that they may have experienced a sense of peace in much the same way those suffering an NDE do. It’s not possible to extrapolate fully from a single case, but let’s imagine for a moment that all brains surge at death, replaying and reimagining the most important moments of life (note: This assumption appears to be backed up, at least in part, by studies in rats). Why? If anything, the case is not the solving of a mystery — it does not reduce the brain or its untraceable wonders so much as enlarge them by asking new questions.
Nature is nothing if not efficient. Though evolutionary processes may make an organism more complex or more simple, the changes are driven by the necessities of preserving a species. A study published in 2021 by Brain Communication indicated that NDE had evolved from thanatosis — the paralytic state we know as “playing dead” to avoid predation.
Possums are perhaps the most famous for this trick, followed by fainting goats and species of snake. The authors proposed that the acquisition of language enabled humans to transform these events into life-recall. The (highly debatable) theory is interesting, but doesn’t make sense of the death-brain-surge. If the brain, as our most highly operating bodily system, chooses to use its last moments to create “realer than real” memories of important events, what benefit does that serve?
We know that a dying tree will send its nutrients out through a “wood wide web” of mycorrhizal fungi, where individual plants join together symbiotically. Science writer Robert MacFarlane explains this intimacy as mutualism: “fungal network also allows plants to distribute resources — sugar, nitrogen, and phosphorus — between one another.” In addition, an injured plant, or one under attack, sends airborne chemical messages to all other surrounding plants that danger is on the way. There are times, therefore, when a surge of energy flows out of the dying organism to benefit those around it. We mimic this same approach in our man-made technologies, such as safety systems that draw power from other areas when under attack, or the frantic uploading of data to the cloud from a failing hard drive. Is it possible that our brains, with their surge of important information and formative memories, are trying to do the same?
It makes for excellent science fiction ruminations. Humans sending out their most important thoughts or memories to others have been explored in fiction as diverse as Arthur Conan Doyle’s The Leather Funnel, the 1983 film Brainstorm, and even the new sci-fi series The OA. There’s no evidence that the surge of activity in the brain ever escapes out of it. But neither do we have an explanation for its presence.
Neurosurgeon-scientist Robert White once compared the brain to a vessel carrying the soul. When challenged that we have no proof of souls, White, a devout Catholic, responded that we have no proof otherwise. And so, even on the heels of our latest discoveries, we return to the mystery that shrouds the last moments between life and death. We may be as uncertain about what that tells us as ever we were — but with even greater appreciation for the mysterious inner-space of our own cerebral processes.
