Serotonergic Modulation of Cognition, Emotion and Brain Activation in Healthy Volunteers

The aim of this project is: * To apply a pharmacological tool of selective serotonin (5-hydroxytryptamine, 5-HT system) reuptake inhibition in healthy humans. Specifically: * To investigate how sub-chronic administration of 20 mg of escitalopram affects cognitive performance (\'cold\' cognition) and social-emotional functioning (\'hot\' cognition) compared with placebo; and * To investigate how sub-chronic administration of 20 mg of escitalopram affects functional brain activation during a paradigm of reinforcement learning following drug administration compared with placebo, and how activation relates to cognitive performance and social-emotional functioning.