The overall objective of this project is to determine the functional integrity of the anterior forebrain mesocircuit (medial frontal cortex, striatum and central thalamus) using a novel tool [11C] flumazenil (FMZ). FMZ binding in the brain reports both neuronal structural and functional integrity. The rationale underlying the proposed research is that quantitative measurements of neuronal structural and functional integrity within the anterior forebrain mesocircuit will correlate with executive attention deficits at an individual level and allow unparalleled and unique insight into the biological underpinnings of the deficits to frame mechanistic approaches for future diagnosis and therapy.