Next Thursday April/2/2015 at 12:00 noon
"Building 75’s first floor conference room"
75 3rd St., Charlestown Navy Yard
Emery N. Brown, M.D., Ph.D.
Institute for Medical Engineering and Science
Department of Brain and Cognitive Sciences
Massachusetts Institute of Technology
Department of Anesthesia, Critical Care and Pain Medicine Massachusetts General Hospital Harvard Medical School
The Dynamics of the Unconscious Brain Under General Anesthesia
General anesthesia is a drug-induced, reversible condition comprised of five behavioral 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 take three approaches 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. Hence, general anesthesia is not a mystery.