Anesthesia and Functional Connectivity: An Analysis of fMRI Changes

Study Summary

Functional connectivity is defined as a correlation in neural activity between distinct regions of the brain. Several recent studies have demonstrated areas of low-frequency functional connectivity inherent to brain tissue at rest. These oscillations can be measured using functional magnetic resonance imaging (fMRI) and appear to be synchronized between related areas of the brain. To date, no investigators have examined the effects of low-dose anesthesia on functional connectivity. This study will image the human brain under conditions of rest, and low-dose anesthetic induced sedation. Quality of the acquired signals will be evaluated and functional networks in the brain will be examined. Of interest is whether administration of a low-dose anesthetic disrupts functional connectivity in the brain, and whether a disruption of functional connectivity is responsible for the reported analgesic and antidepressant effects of a anesthetic. Participation in the study includes four visits: an in-person interview, an initial fMRI scan, the anesthesia infusion, and a second fMRI scan. There is an optional follow-up fMRI scan one week post infusion.

Primary Outcome

The imaging experiments and analysis of subject-specific data will lead to maps corresponding to separate measures: resting state functional connectivity maps. The outcome of interest is whether ketamine reduces functional connectivity between the anterior (subgenual anterior cingulate corte, sgACC) and posterior regions (posterior cingulate cortex, PCC) of the default mode network. This is the z-score of the functional connectivity correlation. Timepoints for Initial fMRI were: Time 1:Immediat

Interventions

• DRUG Anesthetics, Dissociative