Jonathan Rosier

Jonathan Roiser

Professor of Nueroscience and Mental Health

Institute of Cognitive Neuroscience

Div of Psychology & Lang Sciences

University of College London

Title: A computational approach to understanding motivational symptoms in depression

Motivational symptoms of depression are debilitating and associated with poor clinical outcome, but the mechanisms underlying them are poorly understood. This talk will present data examining how cognitive processes related to effort-based decision making for reward are associated with depressive symptoms, using a computational approach. In the first part of the talk results from two cross-sectional behavioural studies, including >250 participants (healthy volunteers, unmedicated depressed patients, first degree relatives and remitted depressed patients), will be presented. Participants completed a rewarded physical effort task using a grip squeeze device, and motivational symptoms were assessed through questionnaires. Data were analyzed using a hierarchical computational approach, with model parameters estimated in a Bayesian framework using sampling. In the non-clinical study (N=90), general depressive symptoms were associated with lower reward sensitivity, while anhedonia was related to a lack of willingness to engage in high effort challenges. In the clinical study (N=180), current or past depression was associated with a lower overall propensity to accept challenges, independent of reward or effort level. Preliminary results from studies examining the effect of L-Dopa on effort-based decisions in healthy and depressed volunteers (N=80) and patients with Parkinson's disease with (N=30) and without depression (N=30) will be presented, with clear effects on effort-based decision making observed only in the latter. Ongoing work examining the impact of physical activity on motivational symptoms and effort-based decisions will be outlined briefly. These studies illuminate the cognitive and brain mechanisms contributing to depressive symptoms related to disrupted motivational processing, providing some clues to potential avenues for intervention strategies for these debilitating symptoms.