Dopamine May Influence "Good" and "Bad" Emotions

Author:  Cathy Tran
Institution:  University of California Santa Barbara
Date:  November 2004

Our understanding of what is emotionally "good" or "bad" may be generated by dopamine transmitters in the brain, according to a study published in the November issue of Science. A team of researchers from the University of Colorado at Boulder found that dopamine concentration is linked to decision-making ability.

This finding is particularly relevant to patients with Parkinson’s disease, which is caused by lower levels of the brain chemical dopamine, explains Michael Frank, a graduate student on the CU-Boulder team. Parkinson’s disease medications artificially increase dopamine in the brain, but the CU-Boulder findings suggest that this surge in dopamine may have negative effects.

Trial-and-error learning tasks were administered to 30 Parkinson’s disease patients and 19 healthy control participants to test how "good" or "bad" outcomes effect decision-making.

Analyses showed that patients on dopamine-supplementing medication learned to choose things associated with positive feedback, or "good" outcomes. Patients who were off the medication learned to avoid things associated with negative feedback, or "bad" outcomes. In contrast, the control participants learned to incorporate both strategies when making decisions.

Frank explains that these differences arise because "when experiencing a loss, dopamine levels are normally low in the brain, and the medication may prevent this from happening."

These findings may have implications for drugs that improve learning and decision-making ability.