After my experience five years ago, and after reading this news today, it is rather difficult for me to imagine a rat in cardiac arrest, seeing light and traveling down a tunnel only to emerge surrounded by a host of winged cheeses and mice angels. news.nationalgeographic/news/2013/08/130814-near-death-brain-life-after-death-bright-light/?google_editors_picks=true A new study shows that even after cardiac arrest, the brain keeps on going... When researchers recorded and analyzed electroencephalograms (EEGs) of the brain activity of rats during cardiac arrest, they discovered that in the seconds after the heart stopped beating, there was a final burst of brain activity characteristic of conscious perception. The finding indicates that the source of the electrical activity in the immediate aftermath of clinical death was the brain itself, not an outside or supernatural source. pnas.org/content/early/2013/08/08/1308285110 Surge of neurophysiological coherence and connectivity in the dying brain. Abstract: The brain is assumed to be hypoactive during cardiac arrest. However, the neurophysiological state of the brain immediately following cardiac arrest has not been systematically investigated. In this study, we performed continuous electroencephalography in rats undergoing experimental cardiac arrest and analyzed changes in power density, coherence, directed connectivity, and cross-frequency coupling. We identified a transient surge of synchronous gamma oscillations that occurred within the first 30 s after cardiac arrest and preceded isoelectric electroencephalogram. Gamma oscillations during cardiac arrest were global and highly coherent; moreover, this frequency band exhibited a striking increase in anterior–posterior-directed connectivity and tight phase-coupling to both theta and alpha waves. High-frequency neurophysiological activity in the near-death state exceeded levels found during the conscious waking state. These data demonstrate that the mammalian brain can, albeit paradoxically, generate neural correlates of heightened conscious processing at near-death.
Posted on: Wed, 14 Aug 2013 18:02:42 +0000
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