Impacts of dopamine on learning and behavior in health and disease: Insights from optogenetics in rodents

Dopamine neurons in the ventral midbrain play important roles in various behavioral functions such as learning, motivation, and movement. The exact mechanisms and algorithms by which dopamine regulates these functions, however, remain to be clarified. Since its introduction in the mid-2000s, optogenetics has played a pivotal role in advancing our understanding of dopamine's functions and mechanisms. This article discusses the role of dopamine in behavioral functions, dividing them into two categories: effects on ongoing behavior (motivation and movement) vs. future behavior (learning), particularly emphasizing the roles that optogenetics has played in these studies. We will then discuss cellular processes underlying these functions as well as insights into dopamine's involvement in symptoms of psychiatric disorders.