[Motivation in all Ks: computational approach to neuro-psychiatric diseases]

Motivation can be defined as the function that orients and activates the behavior. Motivation deficits such as apathy are pervasive in both neurological and psychiatric diseases, and are currently assessed with clinical scales that do not give any mechanistic insight. Here, we present another approach that consists in phenotyping the behaviour of patients in motivation tests, using computational models. These formal models impose a precise and operational definition of motivation that is embedded in decision theory. We then review basic and clinical studies that have investigated the neural bases of motivation processes and shown the involvement of specific cortical, subcortical and neuromodulatory systems. Finally, we emphasize the promises of computational phenotyping for clinical purposes, as it may not only give insight into motivation deficits but also help personalize treatment.