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Dying: What Kind of Experience Is It?

Still from the movie Flatliners

Is it possible that one day in the future, humans can bring a dying person from the brink of death, in the name of science? Image source: movie Flatliners.

When one is dying, will his last hurrah be an explosion of conscious experience?

Not necessarily true, because we can’t get access to others’ brain and record his or her dying experience as pictures. However, a new animal research might give us a tantalizing glimpse of life before death.

Most of us have no idea about what does it look like to die. However, about 1 out of 10 people who survive a cardiac arrest claim that they have near death experiences (NDEs). Such experiences range from relived memories to vivid experiences of sound, light and emotion.

Jimo Borjigin and co-workers at the University of Michigan, conducted an interesting study and published it in PNAS. This new study may be helpful in explaining what is happened in the brain immediately before death. The researchers induced cardiac arrest on rats and measured their electrical activity in the brain with the help of electroencephalography (EEG). They obtained a remarkable observation that prior to death, activity in a particular frequency, i.e., gamma band,  was more than doubled in power comparing with that when animals were awake.

This pattern of brain activity, gamma band, is hauntingly familiar and for year, gamma oscillations have been regarded as a hallmark of human brains’ conscious activities that when we are recalling a memory or aware of a stimulus, waves of activity in the gamma band will pass forth and back between the front and back of the brain. So, does a dying rat have a similar conscious state the period before death?

A short answer is, we don’t know because correlation is not as same as causation. Although we would like to link consciousness and these surges in neutral activity, we face two barriers.

The first barrier is that we don’t know if rats experience their consciousness in the same way as humans do; in other words, we are not sure what this activity profile represents. Second, even if rats are conscious, we could not conclude from the brain activity alone that these activity bursts reflect consciousness. If we do so, we assume that gamma activity is solely associated with consciousness, which is not the case. Therefore, we may fall prey to a logical fallacy known as reverse inference. Borjigin and co-workers worked carefully to avoid such mistake and they didn’t mention in their article that the rats experienced NDEs.

Why should the brain put on such a show before death? Is it an attempt to make sense of highly unusual internal signal, or a coping mechanism for stress? This still remains a mystery. The researchers carefully ruled out pain as an explanation for their findings—they used carbon dioxide, a painless process, instead of cardiac arrest, to induce the death for rats and still observed the same bursts of activity. To address with these questions, we might need to run similar studies on humans but not rats. One possible approach is to record EEG in patients during death. Are you willing to volunteer for this study when you are dying? Another approach is to induce similar bursts of gamma activity when people are awake and test for heightened levels of consciousness. “Using experimental methods that induce increased gamma synchrony in humans and see whether NDEs can be triggered by neurostimulation, might be a way to go beyond correlation to causation.” Said Dr. Dave McGonigle, a neuroscientist from Cardiff University.

Probably, some of us who were children of the 80s might think of an even more pioneering method. Might it be possible that one day in future, we could bring people to the brink of death and back again, just like ocean explorers nearing the edge of the world? Someday in future, dancing with death while doing neuroscience can reveal the ultimate insight into what lies immediately before the eternal sleep.

SourceThe GuardianDying brains: will our last hurrah be an explosion of conscious experience?
Image sourcetheguardian.com