Flashes of lucidity before dying: the debate shaking neuroscience

“My mother had advanced Alzheimer's. She no longer recognized us and seemed indifferent to the strangers who visited her once or twice a week. The day before she died, however, everything changed. Not only did she recognize us, but she wanted to know what had happened to each of us in the past year.” The testimony of a German woman, collected in 2019 by Alexander Batthyány, director of the Viktor Frankl Institute in Vienna, shows a case of what has been dubbed terminal lucidity, a brief return of the self in people who seemed to have disappeared long before due to brain injuries or Alzheimer's.

In his book The Threshold (Errata Naturae), recently published in Spanish, Batthyány recounts his research on this understudied phenomenon, recounting cases of family members and healthcare professionals who witness what appears to be a temporary resurrection of someone they had thought lost. According to his estimates, up to 6% of people who appear to have lost consciousness forever experience this. In an interview with EL PAÍS, the psychologist defends the importance of studying these cases to understand their significance. For him, they challenge the current conception that the mind is merely an emergent property of the brain and that when the brain is damaged, consciousness disappears forever.

For Batthyány, terminal lucidity challenges the "naive materialism" that links capacities such as memory or vision to specific areas of the brain and requires opening up to the possibility that there is a consciousness independent of the brain. "Under normal conditions, perhaps the best model is the materialist one, but as we approach the end, materialism no longer applies," he asserts.

Terminal lucidity and near-death experiences would be an indication to people like Batthyány that, alongside the consciousness that emerges from the brain and disappears when it deteriorates, there is another, protected, ethereal consciousness, hidden during our earthly life by the previous one, but which resurfaces in the final stages of life, finally freed from the shackles of matter. This would explain the final flashes of consciousness or the stories of people who revive after having been clinically dead. That light at the end of the tunnel, the reunion with deceased loved ones, the sensation of ego dissolution and unity with the universe that transmits an indescribable peace and makes many who have the experience lose their fear of death and even yearn for it.

For now, the evidence to support such ambitious hypotheses is scarce, and Batthyány himself acknowledges this. Most of his research, such as that dealing with near-death experiences, relies on the collection of retrospective cases from witnesses who recount what happened—which, in scientific terms, constitutes low-quality evidence. In such extraordinary and unpredictable experiences, it is difficult to apply modern scientific criteria such as measurability, reproducibility, and predictability.

Since Dutch cardiologist Pim van Lommel's landmark study, published in The Lancet in 2001, the field of research into these phenomena has been dominated by those who favor a dualistic interpretation, which asserts that there is a consciousness separate from the brain. This is partly because research into near-death experiences seemed more the task of Cuarto Milenio collaborators than of serious scientists. Now, some mainstream scientists are also beginning to work in this field. This is the case with the Coma Science Group at the University of Liège, Belgium. This year, a team from that group, led by Charlotte Martial, published an article in the journal Nature Reviews Neurology in which they present a neuroscientific model of near-death experiences.

The NEPTUNE model (Neurophysiological and Evolutionary-Psychological Theory for Understanding Near-Death Experiences) posits that these experiences are a cascade of neurophysiological and psychological processes that begin in critical situations. In these circumstances, oxygen deprivation or changes in the brain cause increases in neurotransmitters such as serotonin and dopamine and increase neuronal excitability in some brain regions. This could be behind the vivid sensations, calm, or the feeling of leaving one's body that are characteristic of near-death experiences (NDEs). Furthermore, they propose framing this physiological response within evolutionary theory, as a tool for coping with threats. More than responses, this model provides a framework for conducting rigorous experiments.

Martial believes that the dominance of the dualistic view in the interpretation of NDEs is due, on the one hand, "to the lack of a rigorous and convincing scientific framework to explain these rich, intense, subjective experiences that occur at a time when we would not have expected consciousness." Furthermore, there have been no large-scale experiments in recent decades to test a scientific model of NDEs.

Proponents of dualistic theories of death suggest that what one sees during an NDE or in one's final moments of lucidity is a window into another world where the rules of this one don't apply. Those who experience these brushes with the afterlife return reporting that they were filled with a feeling of peace and harmony with the universe, that they saw themselves separated from their bodies, or that they were surrounded by a bright light. But, as Martial has found, it's not necessary to be close to death to experience these experiences. Stimulating specific parts of the brain with intracranial electrodes can induce similar experiences, as can psychedelic substances. This also happens with fainting spells.

In a recently published article, she and her team studied 22 healthy volunteers who induced syncopes. During their brief fainting spells, 36% reported a subjective experience that met the criteria for an NDE according to a scale developed by psychiatrist Bruce Greyson . Eighty-eight percent had feelings of peace or pleasure, 50% felt joyful, 100% felt like they were leaving their bodies, and 50% believed they had entered another, more ethereal world. This experiment suggests, Martial says, that hypoxia plays an important role in NDEs.

Martial is participating in an experiment to test dualism, hiding signals in the resuscitation room, invisible from the bed, to see if patients can see them. "So far, there are no conclusive results," says the researcher, who acknowledges that, with current technology, such as electroencephalography and magnetic resonance imaging, it won't be possible to test the idea of ​​whether there is a source of consciousness other than the brain.

From Barcelona, ​​supported by the Incloby Foundation, Project Luz is an eight-year study exploring NDEs and their long-term effects. The main objective of the project is to document how people's lives and values ​​change after being resuscitated following a cardiorespiratory arrest. This project is led by Luján Comas, a specialist in Anesthesiology and Resuscitation at Vall d'Hebron Hospital in Barcelona for 32 years: "They experience peace and love, and are able to see people who have died. Many express that they felt like they were coming home and didn't want to return to life." "They come back changed, with other values, more spiritual, although not necessarily religious, they recognize what truly makes sense in life, focusing on love," says Comas.

The specialist believes that "if people have these experiences when the brain is flat and has no electrical activity, the concept that consciousness is only a product of the brain and ends when it stops functioning is incorrect." But she acknowledges that, for now, it's only a hypothesis.

In this leap, in search of scientific support that harmonizes ancestral spiritual intuitions and reason, proponents of the dualist view often turn to quantum physics. Surgeon Manuel Sans Segarra, famous for claiming to have scientific proof of life after death , often appeals to quantum physics as a basis for affirming the existence of an immortal superconsciousness of which we are all a part. But quantum physics "cannot be used to explain these phenomena," in the words of Alberto Casas, CSIC research professor at the Institute of Theoretical Physics in Madrid. "The brain is a macroscopic system, where these quantum effects are diluted," he concludes.

Einstein spoke of phantasmagorical action at a distance, and Comas believes the phenomenon tells us that "everything is interconnected" and that there is a nonlocal consciousness that isn't anchored to an individual brain. Casas explains that "the idea that one brain can be connected to another by a kind of telepathy due to entanglement doesn't hold water." "Furthermore, even if they could become entangled, quantum physics itself implies that no meaningful information could be transmitted," he emphasizes.

Supporters of dualism are eager to go further. This is partly because the materialist explanation, even if true, would offer no relief from the anguish of death, while the spiritual one provides it, whether or not it has a basis in reality. For Comas, recounting these experiences "gives hope that life goes on and gives hope to people who have lost a loved one [...] that you will find yourself again." "I think that's enough; if it helps a person recover, why should we destroy it?" he asks.

Although it remains another unverifiable speculation, Batthyány and Comas's claims fit with the evolutionary explanation for the fact that experiences such as NDEs or people who claim to have had vivid contact with the afterlife appear in all eras and in all human cultures on the planet. They help us live. Those who defend the dualist hypothesis suggest that this universality of the accounts proves that the afterlife is not a hallucination triggered by neural mechanisms. For now, the evidence only allows us to confirm one thing: the human need for solace is insatiable.