British surgeon Dr Sam Parnia declared – the brain remains ‘alive’ after clinical death. Parnia led a research study with a team of scientists from the New York School of Medicine that concluded consciousness of the brain continues after the heart stops beating and the body stops functioning.

Dr Sam Parnia, Director of Intensive Care, New York School of Medicine, said:  “people know that they have died immediately after it happens” – this is due to continuing consciousness of the brain after the body has stopped emitting signs of life.

This is contrary to previous modern scientific research, which suggests that chemical processes associated with the brain of a living being such as thinking, emotions, and consciousness… stop once the body dies.

The team of researchers studied a group of patients who each suffered a cardiac rest, and so technically died.  Medically speaking, the time of clinical death is recorded at the moment that the heart stops beating, and therefore blood stops flowing to the brain. All patients were resuscitated and revived shortly after the ‘clinical’ death and as such were able to recount their experiences.

One of the key concluding points of the study was that patients were aware of whole conversations after clinical death.  Some could recount the actual time of death along with being able to identify people and other things around them.

According to Parnia's team, there is evidence to suggest that an ‘energy boost occurs’ in the brain when a person dies, which could explain the phenomenon of 'near' or actual conscious experiences of death.

In another study from 2013, researchers from the University of Michigan found that, after clinical death occurred in rats, brain activity actually flared. Brief moments after clinical death, the researchers observed activity patterns in the brain related to a 'hyper alert' state – again suggesting an extended consciousness of the brain after death.

What happens to the brain during a heart attack?

A heart attack, in most cases is caused by a clot that blocks one of the coronary arteries. The coronary arteries carry blood and oxygen to the heart. If the arteries are blocked, oxygen cannot reach the heart, which will then cause heart cells to die. As a consequence, electrical signals that control the ‘pumping action’ of the heart are interrupted, the heart then stops beating and death inevitably follows.

During a heart attack the cerebral cortex, the 'thinking part' of the brain, lowers its activity rapidly, and typically within 20 seconds, brain waves cease, or at least those that are visible on a electroencephalography (EEG) monitor. This first reaction initiates a chain of cellular processes that result in brain death. But, according to Dr. Parnia, "until this happens, it can be hours after the heart stops working before brain death occurs."

Performing cardiopulmonary resuscitation (CPR) sends blood to the brain, "approximately 15 percent of what it requires to function normally,” said Parnia. This is enough to slow down the death of brain cells, but it is not enough to start the brain to work again, which is why reflexes do not resume during CPR.

Parnia explained, "If you manage to restart the heart with CPR, little by little the brain will begin to function again. But of course, the longer CPR is performed the more neurons that die, but at a slower pace.”

*References:

'Awareness during resuscitation. A prospective study'. Sam Parnia. Resuscitation Journal. DOI: http://dx.doi.org/10.1016/j.resuscitation.2014.09.004