A University of Michigan study published in the journalProceedings of the National Academy of Sciences(PNAS) this week shows that,shortly after clinical death, which occurs when the heart stops beating and blood stops flowing to the brain,rats exhibit patterns of brain activity characteristic of conscious awareness.
“This study, carried out in animals, is the first to inquire about what happens in the neurophysiological state of the dying brain,” explained Jimo Borjigin, an expert in Physiology and Neurology and co-author of the study. “This research will form the foundation for future human studies investigating the mental experiences that occur in the brain when it is dying, including the vision of light reported by patients with near-death experiences.” Borjigin and his colleagues analyzed the brain activity of nine anesthetized rats undergoing experimentally induced cardiac arrest using electroencephalograms.
During the first thirty seconds following cardiac arrest, all rats exhibiteda generalized and transient increase in highly synchronized activity that had all the characteristics of a highly excited brain. In addition, the authors observed nearly identical patterns in the dying brains of rats that were being suffocated.
“The data confirmed our prognosis that we would find some signals of conscious activity in the brain during cardiac arrest,” Borjigin clarified, although he admits that they were surprised by the high levels of activity, since many known electrical signals of consciousness exceeded the levels. found in the waking state, indicating that the brain is capable of well-organized electrical activity during the initial stage of clinical death.
“The study suggests that the reduction of oxygen, or oxygen and glucose, during cardiac arrest can stimulate brain activity that is characteristic of conscious processing,” emphasizes Borjigin.
