"Supported by an NIH K08 grant from the National Institute of General Medical Sciences, our laboratory is studying the impact of anesthetics on the nervous system, with the longer term goal of understanding how recovery of consciousness from anesthesia occurs. Using a mouse model, we are investigating how individual neuron populations within the brain cortex show changes in electrical activity at different anesthetic depths. This research model causes the neurons to fluoresce when they are stimulated. By selectively targeting and intervening in these neuron populations, we hope to achieve a causal investigation of the changes in the brain that lead to unconsciousness from anesthesia, and the resulting recovery of consciousness after anesthesia. How does the brain recover consciousness after significant perturbations such as anesthesia? The simplest answer is that as the anesthetic washes out, the brain follows a steady and monotonic path toward consciousness. However, our research has shown this simple intuition is incorrect. In one study, we varied the anesthetic concentration to parametrically control the magnitude of perturbation to brain dynamics while analyzing the characteristics of neuronal activity during recovery of consciousness. We find that, en route to consciousness, the brain passes through several discrete activity states. Although transitions between certain of these activity states occur spontaneously, transitions between others are not observed. Thus, the network formed by these state transitions gives rise to an ordered sequence of states that mediates recovery of consciousness. The results of our research suggest a new way to think about the human brain under anesthesia, and could lead to critical reexamination of how we approach monitoring anesthesia in the operating room. Additionally, if the results are applicable to other disorders of consciousness — such as coma or minimally conscious states — we may be better able to predict functional recovery from brain injuries by looking at the spontaneously occurring transitions in brain activity states."

anesthesia