After an elderly patient died suddenly during a routine test, scientists inadvertently collected unique data about activity in his brain at the very end of his life: During the 30 seconds before and after the man went into cardiac arrest, his brainwaves were remarkably similar to those observed during dreaming, reminder recall and meditation, suggesting that people actually see their life “flash before their eyes” when they die.
The phenomenon of past memories repeating themselves when one dies has been reported by some people who have had near-death experiences. But this is the first scientific evidence that this “flash” could be real. However, as this is the only case study, it is impossible to make any further assumptions about how common the phenomenon is or what the experience might be like.
Researchers made the startling discovery in 2016 while examining the brain activity of an 87-year-old Canadian who was developing epilepsy. The team performed an electroencephalogram (EEG) — a test that detects abnormalities in the brain’s electrical activity — to learn more about what was happening during his seizures. Then the man suffered a sudden and fatal blow heart attack. The patient’s unexpected death meant the team accidentally captured the first-ever image of a dying brain, the researchers said said in a statement.
In all, the researchers recorded about 900 seconds of brain activity before and immediately after the patient’s death. This allowed them to see how his neural oscillations — repetitive patterns of neural activity known as brain waves — changed as he died. They found that there was an unusual change in his brain wave activity in the 30 seconds before and after his cardiac arrest.
“Just before and after the heart stopped working, we saw changes in a specific band of neuronal oscillations,” said lead researcher Dr. Ajmal Zemmar, a neurosurgeon at the University of Toronto in Canada at the time of the man’s fall, in the statement. These specific types of vibrations are known as gamma waves, added Zemmar, who is now at the University of Louisville in Kentucky.
Neural oscillations are classified based on their frequency and amplitude. Gamma waves have a frequency between 30 and 100 Hertz, the highest frequency of all vibrations, and are most commonly observed in the brain when people access their memory center, in a region called hippocampusduring dreams.
The team also collected data on other types of vibrations during death, including delta, theta, alpha and beta waves. But it was the gamma waves that suggested the man was replaying memories from throughout his life in his brain – a phenomenon known as life memory.
“By generating vibrations associated with memory retrieval, the brain may play a final memory of important life events just before we die, similar to near-death experiences,” Zemmar said in the statement.
experiments on rats have shown that the rodents experience similar gamma oscillations around the time of death, the statement said. Thus, the researchers speculate that the memory of life may be a universal experience shared by a majority of dying mammalian brains, although there is minimal evidence to support this.
However, the researchers cautioned that it would be premature to definitively claim that the recall is a real phenomenon. The dying man was elderly and had epilepsy, which is known to alter gamma wave activity. This could have meant that his brain activity at death was different than that of someone without epilepsy. Furthermore, there is no way of knowing if the man actually saw or perceived his past memories, or if he was just in a dream-like state brought on by his failure nervous system.
Therefore, much more research is needed to draw firm conclusions about life memory, the researchers warned. The account of the man’s case was not released until six years after his death because researchers hoped to uncover more case studies of dying brains to back up their claims, but they came up empty-handed, according to the report BBC.
However, the findings could offer comfort to friends and family members during the “indescribably difficult” experience of losing loved ones, the researchers said. “Although our loved ones have their eyes closed and are ready to let us rest, their brains may be replaying some of the most beautiful moments they have experienced in their lives,” Zemmar said in the statement.
The case report was published online on February 22 in the journal Frontiers in aging neuroscience.
Originally published on Live Science.
First-ever scan of a dying human brain reveals life may actually ‘flash before your eyes’ Source link First-ever scan of a dying human brain reveals life may actually ‘flash before your eyes’