Death is not a subject we often think about or are even comfortable talking about. In fact, a number of contemporary sociologists believe that despite widespread liberalization of thought in modern times, death is one of the topics where the extent of taboo has actually grown.
Although death is an integral part of life, whether and how the dying brain is capable of generating conscious activity has been vigorously debated.
But in this week’s PNAS Early Edition, a U-M study shows shortly after clinical death, in which the heart stops beating and blood stops flowing to the brain, rats display brain activity patterns characteristic of conscious perception.
"This study, performed in animals, is the first dealing with what happens to the neurophysiological state of the dying brain," says lead study author Jimo Borjigin, Ph.D., associate professor of molecular and integrative physiology and associate professor of neurology at the University of Michigan Medical School.
"It will form the foundation for future human studies investigating experiences occurring in the dying brain, including seeing light during cardiac arrest," she says.
For some scientists, seeing the light during near death experiences is only associated with the brain's attempt to create electrical activity. For others, there's much more to it.
A near-death experience (NDE) refers to personal experiences associated with impending death, encompassing multiple possible sensations including detachment from the body, feelings of levitation, total serenity, security, warmth, the experience of absolute dissolution, and the presence of a light.
These phenomena are usually reported after an individual has been pronounced clinically dead or very close to death. Many NDE reports, however, originate from events that are not life-threatening. With recent developments in cardiac resuscitation techniques, the number of reported NDEs has increased. The experiences have been described in medical journals as having the characteristics of hallucinations, while parapsychologists, those of religious faith and some scientists have pointed to them as evidence of an afterlife and mind-body dualism
Many scientists now believe that near-death experiences cannot be considered as something imagined. On the contrary, the origins could lead them to be perceived although not lived in this reality, but another.
From bright white lights to out-of-body sensations and feelings of life flashing before their eyes, the experiences reported by people who have come close to death but survived are common the world over.
Near Death Experience Research Foundation is the largest NDE website in the world in over 23 languages with thousands of people who have described their NDE in detail.
Researchers analyzed the recordings of brain activity called electroencephalograms (EEGs) from nine anesthetized rats undergoing experimentally induced cardiac arrest.
Within the first 30 seconds after cardiac arrest, all of the rats displayed a widespread, transient surge of highly synchronized brain activity that had features associated with a highly aroused brain.
Furthermore, the authors observed nearly identical patterns in the dying brains of rats undergoing asphyxiation.
"The prediction that we would find some signs of conscious activity in the brain during cardiac arrest was confirmed with the data," says Borjigin, who conceived the idea for the project in 2007 with study co-author neurologist Michael M. Wang, M.D., Ph.D., associate professor of neurology and associate professor of molecular and integrative physiology at the U-M.
"But, we were surprised by the high levels of activity," adds study senior author anesthesiologist George Mashour, M.D., Ph.D., assistant professor of anesthesiology and neurosurgery at the U-M. " In fact, at near-death, many known electrical signatures of consciousness exceeded levels found in the waking state, suggesting that the brain is capable of well-organized electrical activity during the early stage of clinical death."
These pulses are one of the neuronal features that are thought to underpin consciousness in humans, especially when they help to "link" information from different parts of the brain.
The brain is assumed to be inactive during cardiac arrest. However the neurophysiological state of the brain immediately following cardiac arrest had not been systemically investigated until now.
Dr Borjigin said it was feasible that the same thing would happen in the human brain, and that an elevated level of brain activity and consciousness could give rise to near-death experience. The reality of that experience and how it is perceived by a clinically dead patient would be impossible to measure, but there is evidence that something very real occurs after death.
"This study tells us that reduction of oxygen or both oxygen and glucose during cardiac arrest can stimulate brain activity that is characteristic of conscious processing," says Borjigin. "It also provides the first scientific framework for the near-death experiences reported by many cardiac arrest survivors."
This doesn't mean NDE experiences are imagined or that the brain creates an experience that is imagined, but it tells us that
their is clinical evidence of something occuring within the brain that should be otherwise impossible according to what we have previously known about the brain.
"Like 'fire raging through the brain', activity can surge through brain areas involved in conscious experience." But he added: "One limitation is that we do not know when, in time, the near-death experience really occurs. Perhaps it was before patients had anaesthesia, or at some safe point during an operation long before cardiac arrest, and because that point is not measurable, it is impossible for any objective data to be drawn from the NDE subjective experience. In essence, only those experiencing the NDE can provide the details.
Dr. Michael Sabom is a cardiologist whose latest book, Light and Death, includes a detailed medical and scientific analysis of an amazing near-death experience of a woman named Pam Reynolds.
She underwent a rare operation to remove a giant basilar artery aneurysm in her brain that threatened her life. The size and location of the aneurysm, however, precluded its safe removal using the standard neuro-surgical techniques.
She was referred to a doctor who had pioneered a daring surgical procedure known as hypothermic cardiac arrest. It allowed Pam's aneurysm to be excised with a reasonable chance of success. This operation, nicknamed "standstill" by the doctors who perform it, required that Pam's body temperature be lowered to 60 degrees, her heartbeat and breathing stopped, her brain waves flattened, and the blood drained from her head.
In everyday terms, she was put to death. After removing the aneurysm, she was restored to life. During the time that Pam was in standstill, she experienced a NDE. Her remarkably detailed veridical out-of-body observations during her surgery were later verified to be very accurate. This case is considered to be one of the strongest cases of veridical evidence in NDE research because of her ability to describe the unique surgical instruments and procedures used and her ability to describe in detail these events while she was clinically and brain dead.
When all of Pam's vital signs were stopped, the doctor turned on a surgical saw and began to cut through Pam's skull. While this was going on, Pam reported that she felt herself "pop" outside her body and hover above the operating table. Then she watched the doctors working on her lifeless body for awhile. From her out-of-body position, she observed the doctor sawing into her skull with what looked to her like an electric toothbrush.
Pam heard and reported later what the nurses in the operating room had said and exactly what was happening during the operation. At this time, every monitor attached to Pam's body registered "no life" whatsoever. At some point, Pam's consciousness floated out of the operating room and traveled down a tunnel which had a light at the end of it where her deceased relatives and friends were waiting including her long-dead grandmother. Pam's NDE ended when her deceased uncle led her back to her body for her to reentered it. Pam compared the feeling of reentering her dead body to "plunging into a pool of ice."
For practical purposes outside the world of academic debate, three clinical tests commonly determine brain death. First, a standard electroencephalogram, or EEG, measures brain-wave activity. A "flat" EEG denotes non-function of the cerebral cortex - the outer shell of the cerebrum. Second, auditory evoked potentials, similar to those [clicks] elicited by the ear speakers in Pam's surgery, measure brain-stem viability. Absence of these potentials indicates non-function of the brain stem. And third, documentation of no blood flow to the brain is a marker for a generalized absence of brain function.
Some scientists theorize that NDEs are produced by brain chemistry. But, Dr. Peter Fenwick, a neuropsychiatrist and the leading authority in Britain concerning NDEs, believes that these theories fall far short of the facts. In the documentary, "Into the Unknown: Strange But True," Dr. Fenwick describes the state of the brain during a NDE:
"The brain isn't functioning. It's not there. It's destroyed. It's abnormal. But, yet, it can produce these very clear experiences ... an unconscious state is when the brain ceases to function. For example, if you faint, you fall to the floor, you don't know what's happening and the brain isn't working. The memory systems are particularly sensitive to unconsciousness. So, you won't remember anything. But, yet, after one of these experiences [a NDE], you come out with clear, lucid memories ... This is a real puzzle for science. I have not yet seen any good scientific explanation which can explain that fact."
There are three websites devoted to different aspects of consciousness. www.nderf.org (Near death experience), www.adcrf.org (After death communication), and www.oberf.org (everything else that is not a NDE or ADC). These three websites have grown to the largest of their kind in the world. The websites are free. They also have a way to share their experiences with us. Jeff reviews them and I then post them to the website so all can read these remarkable experiences.
"The modern tradition of equating death with an ensuing nothingness can be abandoned. For there is no reason to believe that human death severs the quality of the oneness in the universe." - Larry Dossey, MD
Michael Forrester is a spiritual counselor and is a practicing motivational speaker for corporations in Japan, Canada and the United States.