Abstract: General anesthesia is a drug-induced, reversible condition comprised of five behavioral states: unconsciousness, amnesia (loss of memory), antinociception (loss of pain sensation), akinesia (immobility), and hemodynamic stability with control of the stress response. Our work shows that a primary mechanism through which anesthetics create these altered states of arousal is by initiating and maintaining highly structured oscillations. These oscillations impair communication among brain regions. We illustrate this effect by presenting findings from our human studies of general anesthesia using high-density EEG recordings and intracranial recordings. These studies have allowed us to give a detailed characterization of the neurophysiology of loss and recovery of consciousness due to propofol. We show how these dynamics change systematically with different anesthetic classes and with age. As a consequence, we have developed a principled, neuroscience-based paradigm for using the EEG to monitor the brain states of patients receiving general anesthesia. We demonstrate that the state of general anesthesia can be rapidly reversed by activating specific brain circuits. Finally, we demonstrate that the state of general anesthesia can be controlled using closed loop feedback control systems. The success of our research has depended critically on tight coupling of experiments, signal processing research and mathematical modeling.

Bio: Emery N. Brown is the Edward Hood Taplin Professor of Medical Engineering and Computational Neuroscience at MIT; the Warren M. Zapol Professor of Anaesthesia at Harvard Medical School; and an anesthesiologist at Massachusetts General Hospital. Prof. Brown received his B.A. (magna cum laude) in Applied Mathematics from Harvard College, his M.A. and Ph.D. in statistics from Harvard University and his M.D. (magna cum laude) from Harvard Medical School. He completed his internship in internal medicine at the Brigham and Women’s Hospital and his residency in anesthesiology at MGH. Prof. Brown is an anesthesiologist-statistician whose experimental research has helped define the neuroscience mechanisms of how anesthetics work. He is also widely recognized for his development of signal processing methods for neuroscience data analysis. Prof. Brown served on President Obama’s BRAIN Initiative Working Group. He has received an NIH Director’s Pioneer Award, a Guggenheim Fellowship in Applied Mathematics and the American Society of Anesthesiologists Excellence in Research Award and the Dickson Prize in Science. Prof. Brown is a fellow of the American Academy of Arts Sciences and the National Academy of Inventors. Prof. Brown is a member of the National Academy of Medicine, the National Academy of Sciences and the National Academy of Engineering.