Cue-evoked dopamine promotes conditioned responding during learning

Over the last years, there has been a remarkable surge of interest in the brain mechanisms which underlie how people construct and represent values for the available rewards in their environments. Insight into such value processes is expected to improve our understanding of how people make economic decisions and also to contribute to research on the pathomechanisms of several psychiatric disorders in which decision-making is affected. One proposed seat of neural value signals entails a relatively small population of brain cells which employs dopamine as a neurotransmitter. Whenever an individual is confronted with a predictive cue which, by experience, has become associated with an actual reward, these brain cells respond with an increase in activity. Such response supposedly triggers a feeling of 'wanting' to pursue the reward linked to the predictive cue. However, this is just one of the many theories regarding the function of dopamine cells and the scientific methods used in past research did not allow firm conclusions. A new powerful technique called 'optogenetics' can now overcome much of the limitations because it allows direct manipulation of well-defined neuron types with millisecond precision. Here, we will employ this technique to briefly activate and inactivate dopamine responses to reward-predicting cues. By performing such manipulations, we will be able to finally provide causal evidence for the role of dopamine neurons in subjective valuation.

Publication year:2020