“Our work delineates for the first time the precise brain circuitry in which learning about rewarding and aversive outcomes occurs,” Lammel said. “Having separate neuronal correlates for appetitive and aversive behavior in our brain may explain why we are striving for ever-greater rewards while simultaneously minimizing threats and dangers. Such balanced behavior of approach-and-avoidance learning is surely helpful for surviving competition in a constantly changing environment.” The newly discovered role for dopamine aligns with an increasing recognition that the neurotransmitter has quite different roles in different areas of the brain, exemplified by its function in voluntary movement, which is affected in Parkinson’s disease. The results also explain earlier conflicting experiments, some of which showed that dopamine increases in response to aversive stimuli, while others did not. - neurosciencenews.com