A Human Proof of Concept Study for [11C]-RO5011232 as Radiotracer and Study of the Binding of RO4917523 to Human mGlu5 Brain Receptor at Steady-State in Healthy Volunteers

Inclusion Criteria: * Healthy male and female volunteers as determined by medical history, physical examination, 12-lead ECG, and routine clinical laboratory measurements * Age 18 to 65 years inclusive * Body mass index (BMI) between 18 to30 kg/m2 inclusive and body weight at least 50 kg * Appropriate body size (less than 195 cm \[6 feet and 5 inches\]) in order to accommodate the whole body scanning Exclusion Criteria: * History of or presence of clinically significant psychiatric condition, as evaluated by a psychiatrist before enrolment * History of head trauma with prolonged loss of consciousness (\>10 minutes) or any neurological condition or a history of migraine headaches * Contraindications to MRI procedures (Part I, III and IV) * Subjects suffering from claustrophobia or who would be unable to undergo magnetic resonance imaging (MRI) or PET scanning * Positive pregnancy test at screening or on any day preceding a PET scan * Lactating women * Positive for hepatitis B, hepatitis C or HIV infection * Any history of alcohol or drug abuse within the last 6 months * Regular smoker or nicotine user (\>10 cigarettes per day) * Participation in an investigational drug or device study within three months prior to screening