A Molecular and Functional Brain Imaging Study in Individuals With Down Syndrome and Healthy Controls Following Single Dose RG1662

This single-center, double-blind, placebo-controlled, parallel-group study with crossover component will evaluate the GABAAalpha5 receptor expression, occupancy and functional connectivity in the brains of individuals with Down syndrome and healthy controls following single dose RG1662. On two separate visits, no less than 96 hours and no more than 6 weeks apart, subjects will receive a single oral dose of either RG1662 or placebo followed by positron emission tomography (PET) and magnetic resonance imaging (MRI) scans.