Complexities and paradoxes in understanding the role of dopamine in incentive motivation and instrumental action: Exertion of effort vs. anhedonia.

Instrumental behavior is a very complex and multifaceted process. Behavioral output during instrumental performance is influenced by a variety of factors, including associative conditioning, directional and activational aspects of motivation, affect, action selection and execution, and decision-making functions. Detailed assessments of instrumental behavior can focus on the temporal characteristics of instrumental behavior such as local frequency and response duration, and biophysical measures of response topography such as force output over time.