Death Works Overtime: How The Dying Brain Sparks Vivid Experiences

Saturday - May 13 2023, 20:14 UTC - 1 year ago

As Dr. Jimo Borjigin of the University of Michigan led a new study consisting of 4 comatose patients, electrical signals in the brain suggested death may explain near-death experiences and other forms of consciousness as a surge of activity in the dying brain. This neurobiological paradox may be based on individual neurochemicals and brainwave patterns.

We often think of death as an on-off switch. One minute you’re there, and the next it’s lights out.

Not so. During heart failure—one of the largest medical killers globally—the brain gradually loses access to oxygen in the blood, but sparks of activity linger. Far from the last gasp of the brain’s descent into permanent unconsciousness, scientists have long thought these electrical signals may explain near-death experiences, and more broadly, consciousness.

Reports of near-death experiences span various ages, cultures, and ethnicities. The luckily revived few often describe vivid visions of tunnels of white light, floating outside their own bodies, or reconnecting with departed loved ones.

To Dr. Jimo Borjigin at the University of Michigan School of Medicine, Ann Arbor, these "realer-than-real" shared experiences suggest a common, if paradoxical, theme: rather than having its electrical lights flipped off, dying actually triggers a surge of activity in the human brain.

A new study led by Borjigin hints at the first proof of concept of the radical idea. As four comatose patients were sustained by life support, her team detected a surge of brain activity in two of them following withdrawal as they passed on.

The neural activity patterns are far from random. The dying brain generated waves of gamma band activity, a fast oscillating electrical wave that’s often associated with conscious processing and thoughts. The team detected these signals both within a critical "hot zone" and other brain regions previously linked to consciousness.

To be clear, it’s highly unlikely the comatose participants regained consciousness right before death. Rather, the study shows that the dying brain generates a swan song—one that may explain lucid visions and out-of-body experiences as they occur in the mind.

"How vivid experience can emerge from a dysfunctional brain during the process of dying is a neuroscientific paradox. Dr. Borjigin has led an important study that helps shed light on the underlying neurophysiological mechanisms," said study author Dr. George Mashour, the founding director of the Michigan Center for Consciousness Science.

Consciousness comes in two flavors. One is overt: the person is alert and can easily interact with the outside world. The more mysterious half is covert. Here, the person may be conscious in the sense that they are aware of themselves and their surroundings, but unable to show it. This often happens in people with brain injuries such as trauma, stroke, or locked-in syndrome. Back in 2006, a study measuring brain activity using fMRI from a young woman who appeared vegetative surprisingly found that her brain responded to different cognitive tasks even though her body couldn’t. Subsequent studies used EEG (electroencephalography) to probe for signs of consciousness in unresponsive people—including the comatose and the dying.

Borjigin is no stranger to studying the dying brain. Back in 2013, her team ran a seminal trial in nine rats, measuring their brain waves as heart failure took over. Previous attempts at hunting down the neurobiological underpinnings of near-death experiences and consciousness during the dying process had mostly focused on individual neurochemicals, such as dopamine and glutamate. Few had dug into the brain’s electrical activity.