|
|
|
 |
|
Samuel McClure
Center for the Study of Brain, Mind and Behavior, Princeton University, USA
Monday 3 July 2006, 15:00
Seminar Room B10 (Basement)
Alexandra House, 17 Queen Square, London, WC1N 3AR
Dopamine and norepinephrine interactions in decision-making
Recent experimental evidence has suggested that dopamine and norepinephrine may play complimentary roles in selecting actions and seeking rewards. Dopamine is known to emit a reward prediction error signal which may then be used to update action values and enable decisions to exploit current knowledge of expected reward outcomes. Norepinephrine, by contrast, is believed to control the volatility of the decision-making process and may therefore mediate exploration of under-explored actions. We have developed a connectionist model to capture and investigate the interaction of these two neural systems. We demonstrate the efficacy of the model in the context of a reversal task, and propose that norepinephrine enables significantly faster responses to changes in reward contingency than if dopamine were functioning alone. I will conclude with some recent experimental work in which we use empirically measured behavioral adjustment effects to further constrain the model.