The Dynamics of the Unconscious Brain Under General Anesthesia

Emery Brown
Edward Hood Taplin Professor of Medical Engineering, Professor of Computational Neuroscience; Associate Director, Institute of Medical Engineering and Science, MIT; Warren M. Zapol Professor of Anesthesia, Harvard Medical School and Massachusettes General Hospital; Anesthesiologist, MGH.
Thursday, November 14, 2013 - 12:00pm
Galbraith 202
General anesthesia is a drug-induced, reversible condition comprised of five behavioural states: unconsciousness, amnesia (loss of memory), analgesia (loss of pain sensation), akinesia (immobility), and hemodynamic stability with control of the stress response. The mechanisms by which anesthetic drugs induce the state of general anesthesia are considered one of the biggest mysteries of modern medicine. We study three problems to decipher this mystery. First, we present findings from our human studies of general anesthesia using combined fMRI/EEG recordings, high-density EEG recordings and intracranial recordings which have allowed us to give a detailed characterization of the neurophysiology of loss and recovery of consciousness due to propofol. Second, we present a neuro-metabolic model of burst suppression, the profound state of brain inactivation seen in deep states of general anesthesia. We show that our characterization of burst suppression can be used to design a closed-loop anesthesia delivery system for control of a medically-induced coma. Finally, we demonstrate that the state of general anesthesia can be rapidly reversed by activating specific brain circuits. Our results show that it is now possible to have a detailed neurophysiological understanding of the brain under general anesthesia, and that this understanding, can be used to control anesthetic states.
IBBME Distinguished Lecture Series
Sleep & Biological Rhythms Toronto