Brain Networks and Consciousness
Brain Networks and Consciousness
General anesthesia (GA) is a medically induced state of unresponsiveness and unconsciousness,
 which millions of people experience every year. Despite its ubiquity, a clear and consistent
 picture of the brain circuits mediating consciousness and responsiveness has not emerged.
 Studies to date are limited by lack of direct recordings in human brain during medically
 induced anesthesia. Our overall hypothesis is that the current model of consciousness,
 originally proposed to model disorders and recovery of consciousness after brain injury, can
 be generalized to understand mechanisms of consciousness more broadly. This will be studied
 through three specific aims. The first is to evaluate the difference in anesthesia
 sensitivity in patients with and without underlying basal ganglia pathology. Second is to
 correlate changes in brain circuitry with induction and emergence from anesthesia. The third
 aim is to evaluate the effects of targeted deep brain stimulation on anesthesia induced loss
 and recovery of consciousness. This study focuses on experimentally studying these related
 brain circuits by taking advantage of pathological differences in movement disorder patient
 populations undergoing deep brain stimulation (DBS) surgery. DBS is a neurosurgical procedure
 that is used as treatment for movement disorders, such as Parkinson's disease and essential
 tremor, and provides a mechanism to acquire brain activity recordings in subcortical
 structures. This study will provide important insight by using human data to shed light on
 the generalizability of the current model of consciousness. The subject's surgery for DBS
 will be prolonged by up to 40 minutes in order to record the participant's brain activity and
 their responses to verbal and auditory stimuli.
Inclusion Criteria:

 -  Willingness and ability to cooperate during conscious operative procedure for up to 40
 minutes

 -  Clinical diagnosis of Parkinson's disease or essential tremor

 -  Preoperative MRI without evidence of cortical or subdural adhesions or vascular
 abnormalities

 Exclusion Criteria:

 -  Patients with recent use (within one week) of anticoagulant or antiplatelet agent use

 -  Neurocognitive testing indicating amnestic cognitive deficits

 -  History of intolerance of propofol or medical indications to use an anesthetic other
 than propofol