“My life flashed before my eyes.” The phrase is a common metaphor, meant to suggest that someone survived a near-death experience or another close call. But the phrase also has scientific origins, rooted in a process known as “life recall” that is said to occur in the moments before death. The phenomenon has been an ongoing source of mystery for neuroscientists – but now, a new study published in Frontiers in Aging Neuroscience could shed light on the brain processes behind the procedure. Read on to find out more about the ability of the human brain to generate coordinated neuronal activity during a “near-death experience.”
What Is a Near-Death Experience?
When you hear the phrase “near-death experience,” you might think of a horror film that involves a terrifying brush with death. The reality is a bit less dramatic, though no less fascinating. Near-death experiences, or NDEs, have been described as similar to a “panoramic life review” involving memory recalls, hallucinations, and a surreal meditative state. The experiences are most often reported in situations where the brain seems to “transition toward death” – but what are the neurophysiological processes behind the phenomenon? That remains unclear, although some studies with animal models have shown increased activity of the gamma-band during cardiac arrest.
Neuronal Activity in Memory Recall
Thus far, the neurophysiological processes behind the phenomenon have remained unclear. However, scientists have suggested that these “memory flashbacks” may be linked to neural oscillations, or brainwave activity, similar to that involved in everyday functions like memory recall and dreaming. In addition to gamma-band activity, alpha-band oscillations also seem to be key to this process, aiding in visual information processing. Delta band activity may serve a similar function; theta rhythms may also aid in memory recall, especially in verbal and spatial memory tasks. With those functions in mind, one research team set out to explore the role of different neurological activities in near-death experiences.
How Neuronal Activity Impacts NDEs
The new study published in Frontiers in Aging Neuroscience was designed by measuring neuronal activity during a near-death experience. In the study, the researchers evaluated a continuous electroencephalography (EEG) recording from a dying human brain midway through cardiac arrest. After the cardiac arrest event, the researchers found that delta, beta, alpha, and gamma power were decreased in the brain – but a “higher percentage of relative gamma power was observed,” even after cerebral blood flow ceased. In other words, the team reported continuous EEG recording from a human brain “across the transition period to death.” This suggests an “intricate interplay between low- and high-frequency bands” that takes place after cerebral activity begins to cease and lasts into the post-cardiac arrest period. Essentially, these findings suggest that the human brain may remain “active and coordinated during and even after the transition to death,” which could indicate an important role of neuronal activity even as the brain dies.
While the brain’s “stereotyped activity patterns” are still unclear during death, the research does present an interesting possibility: that the human brain orchestrates “near-death experiences” in a way that is much less random than previously understood. This is just the latest in an ongoing scientific effort to uncover the neurological mysteries associated with death.
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