Scientists learn what happens a few seconds after death – the activity of the brain and heart increases
The “light at the end of the tunnel” that a person experiences just before death can be caused by a burst of energy similar to a seizure at the time of death.
Researchers from the University of Michigan found that people experience a spike in gamma wave activity in the area of the brain responsible for consciousness, dreams, and hallucinations just before death.
They believe that these hallucinations are responsible for reports of people seeing bright lights, hearing voices, singing, or even visions of loved ones when death is near.
The study is still in its early stages – only four patients are involved – but scientists hope it will pave the way for a better understanding of how the brain responds to death.
Using an instrument that measures brain waves, the researchers found that some people experience a burst of gamma waves moments before death. This burst of activity may be responsible for the hallucinations a person experiences before death, such as “the light at the end of the tunnel.”
The researchers who published their conclusions on Monday at PNASstudied four patients who died after cardiac arrest during electroencephalogram (EEG) monitoring.
An EEG is a test that measures the electrical activity of the brain using electrodes attached to the scalp.
These devices detect and record tiny electrical signals from the brain. Four patients included in the study were comatose and unresponsive.
Ultimately, they were determined that they could not receive medical attention and, with the permission of their families, they were taken off life support.
When the ventilator keeping them alive was removed, two patients experienced an increase in heart rate along with a spike in gamma wave activity.
Gamma wave activity is considered the fastest in the brain and is associated with consciousness.
High gamma levels are usually associated with intense thinking and increased attention.
Previous research has shown People with schizophrenia often experience bursts of high gamma waves in the brain.
High levels of gamma waves are also recorded when a person has a seizure.
Both study participants who experienced high gamma activity before death had previously experienced seizures in their lives, but not an hour before death.
It is also associated with psychosis and some harmful brain activity such as delusions and hallucinations.
The other two patients did not have the same increase in heart rate, nor did they have increased brain activity.
The study follows an animal study conducted nearly a decade earlier.
Similar signs of gamma activation have been reported in the dying brains of both animals and humans upon loss of oxygen following cardiac arrest.
Because the sample size was small, the team cautions against making any global claims about the implications of the results.
They also point out that it is impossible to know what the patients went through because they did not survive.
Co-author, Dr. George Mashur, founding director of the Michigan Center for the Study of Consciousness, said: “How vivid experiences can emerge from a dysfunctional brain in the process of dying is a neuroscience paradox.”
“Dr. Borjigin has conducted important research that helps shed light on underlying neurophysiological mechanisms.”
Lead author Professor Jimo Borjigin of the University of Michigan said: “We cannot correlate the observed neural signatures of consciousness with corresponding experiences in the same patients in this study.
“However, the observed results are definitely interesting and provide a new basis for our understanding of latent consciousness in dying people.”
Larger studies may provide much-needed data to determine whether these bursts of gamma-ray activity are evidence of hidden consciousness even in death.