The research has been published in the Proceedings of the National Academy of Sciences.
Unlocking the mysteries of the brain has involved neuroscientists from all across the world. Researchers have now discovered a puzzling spike in activity in the brains of two individuals as they approached death and passed away.
The science of the brain and what transpires in the brief minutes before a person’s brain entirely shuts down and dies have long been the subject of research.
Gamma waves have previously been observed to increase as animals enter cardiac and respiratory arrest.
Brain during the final moments of a person dying
The human brain has recently been found to exhibit a comparable activity. Gamma waves are present during conscious perception and are linked to memory processing in the brain.
Researchers from the US-based University of Michigan examined the electroencephalogram (EEG) and electrocardiogram (ECG) signals in four terminally ill patients before and after the removal of ventilatory support in order to gain a better understanding of what transpires in the brain during the final minutes of a person dying. The four patients were all unconscious.
ECG is used to assess the health of the heart, whereas EEG is used to measure the electrical activity of the brain by detecting signals that are produced by the neurons.
Researchers discovered that in two of the patients, hypoxia was accompanied by an increase in gamma activity, according to data published in the Proceedings of the National Academy of Sciences.
It is unclear how the brain works just before cardiac arrest. Although cardiac arrest is generally accompanied by the loss of overt awareness, researchers claimed in the report that it is unknown whether people can experience hidden consciousness while they are dying.
What the team found
Researchers examined cases of patients who passed away in the neuro-intensive care unit at Michigan Medicine, the academic medical centre of the University of Michigan, from 2014. They observed a sudden increase in gamma waves in one region of the brain that created a long-distance link between the two hemispheres of the brain.
The team said that it is still unclear whether the dying human brain activates the posterior cortical areas, which are found in the rear of the head and are in charge of processing visual information.
The hot zone, a region of the brain connected with dreaming and epileptic patients who claim to experience visual hallucinations, is where the gamma wave was first discovered. It is well recognised that the heated zone in the brain is important for conscious processing. The higher gamma waves prevented the patients from surviving to report what they saw, though.
These observations show that the dying brain can continue function, even though the processes and physiological importance of these findings need to be completely examined. They also suggest that the function of the brain during cardiac arrest needs to be reconsidered.