A computational role for dopamine delivery in human decision-making

Recent work suggests that fluctuations in dopamine delivery at target struc tures represent an evaluation of future events that can be used to direct l earning and decision-making. To examine the behavioral consequences of this interpretation, we gave simple decision-making tasks to 66 human subjects and to a network based on a predictive model of mesencephalic dopamine syst ems. The human subjects displayed behavior similar to the network behavior in terms of choice allocation and the character of deliberation times. The agreement between human and model performances suggests a direct relationsh ip between biases in human decision strategies and fluctuating dopamine del ivery. We also show that the model offers a new interpretation of deficits that result when dopamine levels are increased or decreased through disease or pharmacological interventions. The bottom-up approach presented here al so suggests that a variety of behavioral strategies may result from the exp ression of relatively simple neural mechanisms in different behavioral cont exts.