Sex differences in lever pressing and running wheel tasks of effort-based choice behavior in rats: Suppression of high effort activity by the serotonin transport inhibitor fluoxetine.

Selective serotonin transport (SERT) inhibitors such as fluoxetine are the most commonly prescribed treatments for depression. Although efficacious for many symptoms of depression, motivational impairments such as psychomotor retardation, anergia, fatigue and amotivation are relatively resistant to treatment with SERT inhibitors, and these drugs have been reported to exacerbate motivational deficits in some people. In order to study motivational dysfunctions in animal models, procedures have been developed to measure effort-related decision making, which offer animals a choice between high effort actions leading to highly valued reinforcers, or low effort/low reward options.

The Psychopharmacology of Effort-Related Decision Making: Dopamine, Adenosine, and Insights into the Neurochemistry of Motivation.

Effort-based decision making is studied using tasks that offer choices between high-effort options leading to more highly valued reinforcers versus low-effort/low-reward options. These tasks have been used to study the involvement of neural systems, including mesolimbic dopamine and related circuits, in effort-related aspects of motivation. Moreover, such tasks are useful as animal models of some of the motivational symptoms that are seen in people with depression, schizophrenia, Parkinson's disease, and other disorders.