“As the brain begins to change and start to die, different parts become excited, and one of the parts that becomes excited is the visual system,” [director of UCLA Brain Injury Research Center David] Hovda explains. “And so that’s where people begin to see light.”
Recent research points to evidence that the sharpening of the senses some people report also seems to match what we know about the brain’s response to dying. Jimo Borjigin, a neuroscientist at the University of Michigan, first became intrigued by this subject when she noticed something strange in the brains of animals in another experiment: Just before the animals died, neurochemicals in the brain suddenly surged. While scientists had known that brain neurons continued to fire after a person died, this was different. The neurons were secreting new chemicals, and in large amounts.
“A lot of cardiac-arrest survivors describe that during their unconscious period, they have this amazing experience in their brain,” she says. “They see lights and then they describe the experience as ‘realer than real.’” She realized the sudden release of neurochemicals might help to explain this feeling.
Borjigin and her research team tried an experiment. They anesthetized eight rats, and then stopped their hearts. “Suddenly, all the different regions of the brain became synchronized,” she says. The rats’ brains showed higher power in different frequency waves, and also what is known as coherence—the electrical activity from different parts of the brain working together.
“If you’re focusing attention, doing something, trying to figure out a word or trying to remember a face—when you’re doing high-level cognitive activity, these features go up,” Borjigin says. ...
[A] half-dreaming, half-waking state is common in dying people. In fact, researchers led by Christopher Kerr at a hospice center outside Buffalo, New York, conducted a study of dying people’s dreams. Most of the patients interviewed, 88 percent, had at least one dream or vision. And those dreams usually felt different to them from normal dreams. For one thing, the dreams seemed clearer, more real. The “patients’ pre-death dreams were frequently so intense that the dream carried into wakefulness and the dying often experienced them as waking reality,” the researchers write in the Journal of Palliative Medicine.
Seventy-two percent of the patients dreamed about reuniting with people who had already died. Fifty-nine percent said they dreamed about getting ready to travel somewhere. Twenty-eight percent dreamed about meaningful experiences in the past. (Patients were interviewed every day, so the same people often reported dreams about multiple subjects.)
For most of the patients, the dreams were comforting and positive. The researchers say the dreams often helped decrease the fear of death. “The predominant quality of pre-death dreams/visions was a sense of personal meaning, which frequently carried emotional significance for the patient,” they report.
In patients’ final hours, after they’ve stopped eating and drinking, after they’ve lost their vision, “most dying people then close their eyes and appear to be asleep,” says Hallenbeck, the Stanford palliative-care specialist. “From this point on … we can only infer what is actually happening. My impression is that this is not a coma, a state of unconsciousness, as many families and clinicians think, but something like a dream state.”
--Jennie Dear, The Atlantic, on the drift into eternity