Researchers discover mysterious brain activity in the dying

Floating over his body, life unfolding in front of you like in a movie, walking towards a bright white light in a tunnel, a feeling of weightlessness, peace, bliss, encounters with the dead. This is how people who almost died often describe their near-death experience (NDE). Although these are subjective experiences, these descriptions are often very similar, regardless of the cultural background of those affected.

Cause of near-death experiences completely unclear

According to the International Association of Near Death Studies (IANDS), it is now known that near-death experiences have general characteristics that occur in people of all cultures, regardless of age and gender – combined with very individual experiences.

To this day, it is not known exactly what exactly causes these near-death experiences. There are various explanations, ranging from neurological to chemical processes in the brain such as

• lack of oxygen
• excess carbon dioxide
• effects of drugs and
• Hallucination.

Despite decades of research, the cause remains in the dark. “No single physiological or psychological model explains all the common features of NDE,” says American psychiatrist Bruce Greyson, one of the leading researchers in this field.

Gamma waves: Scientists measure increased brain activity in the dying

Years ago, scientists at the University of Michigan encountered a strange phenomenon in animal experiments. In rodents, they found that the brain is still active up to 30 seconds after cardiac arrest. A new study by the researchers, published in Proceedings of the National Academy of Sciences, now shows that this is also the case in people who are dying.

To do this, they examined the brain activities of four patients who were in a coma. Facing no chance of survival, they were removed from life support devices in consultation with their families while their brain activity was continuously monitored.

In two of the patients, the neuronal activity in the form of gamma waves increased drastically shortly after the ventilators were switched off. These are the fastest brainwaves associated with high levels of mental activity and mental peak performance.

According to the study, this increase continued for seconds after the heart stopped beating. In one patient, the production of gamma waves during the dying process even briefly increased to three hundred times the previous levels, much higher than in fully conscious people.

Gamma waves indicate latent consciousness

The increased gamma activity was mainly in the posterior region of the brain, which is associated with dreams and altered states of consciousness, among other things. Cardiac arrest is usually accompanied by a loss of consciousness. However, the increased brain activity indicates that a hidden consciousness might actually be activated during the dying process.

However, since this is a very small study, the authors point out that no general statements can be derived from their observations of activated brain activity when dying – especially since it is not known what the patients would have experienced in these moments.

“We are unable to correlate the observed neural signatures of consciousness with a corresponding experience in the same patients in this study,” says University of Michigan neurologist Nusha Mihaylova, who was involved in the study. Nevertheless, the results are important because they offer a new framework for our understanding of the covert consciousness of dying people.

Neurosurgeon already made similar observation with gamma waves in the dying

Neurosurgeon Ajmal Zemmar from the University of Louisville has a similar view. He too had found increased gamma wave activity in a person who was being monitored clinically and who died of a heart attack. The “Science” portal quotes the scientist as saying that the observation points to a biological mechanism in the brain that repeats memorable events in these final moments.

Gamma waves could be an indication that different brain regions work together to combine different sensations in the conscious perception of an object – for example the sight, smell and sound of a car, the scientist continues. But how exactly this works in the brain is “one of the biggest mysteries in neuroscience”.

The near-death researcher and psychiatrist Bruce Greyson and the Dutch cardiologist Pim van Lommel see the study critically. In a paper they published on the IANDS website, they write that the patients in the study did not have cardiac arrest but were disconnected from mechanical ventilation. The electrical activities in the brain were therefore measured when the patients had not yet experienced complete cardiac arrest according to the EKG. It is therefore questionable whether the electrical activities in the brain that were measured in this phase could actually be linked to a consciousness process.