PET Analysis was based on a Region of Interest (ROI) methodology. A structural MR scan was co-registered with the subject’s PET scans. ROIs were drawn in the primary areas of post-synaptic dopamine release, namely the anterior ventral striatum, posterior ventral striatum, caudate and putamen (figure S1). The anterior ventral striatum was defined as striatum anterior and inferior to the anterior commisure. The posterior ventral striatum was defined as striatum posterior and inferior to the anterior commisure. The PET data from the placebo session were used as a measure of baseline raclopride binding potential, using the simplified reference tissue model 29. Percent change in binding potential (%ΔBP) following alcohol was calculated as (BPplacebo - BPalcohol)/( BPplacebo). Reduction in raclopride binding is attributed to competition with dopamine endogenously released by the alcohol challenge, and the percent change in binding potential has been shown to be proportional to the magnitude of dopamine release 16.
