Procedures

• 1. Ten minutes before the fluorodeoxyglucose (FDG) injection, participants were given practice trials on a continuous performance task (CPT)
• 2. The participant was then transferred to a PET scanner where the brain was scanned in 10mm horizontal slices
• 3. thirty seconds before injection, the task was started so that initial task novelty would not affect the results of the PET scan
• 4. The FDG tracer was injected into each participant
• 5. The FDG was taken up by the brain for a 32-minute period during which the participant completed a continuous performance task (CPT)