Mysterious activity in dying people’s brains 2023

Researchers from all over the world have contributed to the effort to decode the brain’s inner workings. Two patients on the verge of death and during the process of dying have had a strange increase in brain activity uncovered by researchers.

Scientists have long pondered the question of what happens physiologically in the brain in the moments just before death. When animals go into cardiac and respiratory arrest, previous research has shown an increase in gamma waves.

University of Michigan researchers looked studied electroencephalogram (EEG) and electrocardiogram (ECG) data in four terminally ill patients before and after ventilatory assistance was withdrawn to get insight into what happens in the brain during the final minutes of life. All four of the patients had entered a comatose state.

In two cases, PNAS researchers found widespread hypoxia with increased gamma activity.

There is a lack of knowledge about brain function during cardiac arrest. Cardiac arrest is known to be connected with a loss of overt awareness, but “it is unclear whether patients can possess covert consciousness during the dying process,” the paper’s authors write.

Researchers at the University of Michigan analyzed cases of patients who had died in the neuro-intensive care unit at Michigan Medicine since 2014. They found an abrupt increase in gamma waves in one region, which linked the two halves of the brain together.

The gamma wave was first spotted in the brain’s hot zone, which has long been linked to dreaming and to the visual hallucinations experienced by some epileptic patients. Consciousness is thought to be processed mostly in what is called the “hot zone” of the brain.

Unfortunately, because to the increased gamma radiation, none of the patients lived to share their experiences.

While further research is needed to determine the underlying mechanisms and physiological significance of these results, the data presented here show that brain activity persists even in the final stages of death. The findings “also imply the need to reevaluate the role of the brain during cardiac arrest,” the authors write.