Consciousness is one of the biggest mysteries of the brain. But maybe even more intriguing is what goes on when we lose consciousness—and how do we find our way back? Now, researchers studying anesthetized rats have discovered a handful of activity patterns that may help mark the path to consciousness. The findings are in the Proceedings of the National Academy of Sciences. [Andrew E. Hudson et al, Recovery of consciousness is mediated by a network of discrete metastable activity states]



The anesthetized brain is not actually quiet. It shows patterns of spontaneous activity that can change over time. But as the brain wakes, how do these random splashes of activity morph into the vigorous chatter of the conscious mind?



To find out, researchers looked for common patterns in the brain activity of rats as they were put under anesthesia and brought back. And they discovered a number of patterns that took place consistently. A few seemed to serve as stepping stones from deep anesthesia to waking, as if the brain were finding its way through a maze of possible activity states on the way back to consciousness.



Knowing how the brain reboots itself may help physicians better predict recovery from brain injury or even coma, and should lead to a better understanding of how to keep us under.



—Karen Hopkin



[The above text is a transcript of this podcast.]