This study will evaluate the relationship between basmisanil plasma concentrations and the occupancy of Gamma-Amino Butyric Acid A (GABAA) receptor subtypes containing an alpha5 (α5) subunit in healthy Japanese volunteers. Each participant will have two post-screening imaging sessions. In the first imaging session, participants will have a baseline Positron Emission Tomography (PET) scan. In the second imaging session, participants will receive a single oral dose of basmisanil, followed by two on-treatment PET scans at about 4 and 10 hours post-dose.

Inclusion Criteria:

• Male or female Japanese healthy volunteer, who was born in Japan, has 4 ethnically Japanese grandparents and has lived outside Japan for no longer than 5 years
• A body mass index (BMI, Quetelet index) in the range 18.0 to 32.0 kilograms per square meter (kg/m^2)
• Willingness and ability to comply with study restrictions

Exclusion Criteria:

• A history of epilepsy, convulsions or significant head injury, or other structural brain abnormality
• Pregnant or lactating or not using acceptable contraception
• Presence or history of severe adverse reaction to any drug or a history of sensitivity to basmisanil or the PET radioligand (RO15-4513)
• Significant exposure to radiation within the previous 12 months
• Any other clinically relevant abnormalities, concomitant diseases or ongoing medical conditions