Rigoli, F;
Chew, B;
Dayan, P;
Dolan, RJ;
(2016)
The Dopaminergic Midbrain Mediates an Effect of Average Reward on Pavlovian Vigor.
Journal of Cognitive Neuroscience
, 28
(9)
pp. 1303-1317.
10.1162/jocn_a_00972.
Preview |
Text
Dayan_jocn_a_00972.pdf Download (634kB) | Preview |
Abstract
Dopamine plays a key role in motivation. Phasic dopamine response reflects a reinforcement prediction error (RPE), whereas tonic dopamine activity is postulated to represent an average reward that mediates motivational vigor. However, it has been hard to find evidence concerning the neural encoding of average reward that is uncorrupted by influences of RPEs. We circumvented this difficulty in a novel visual search task where we measured participants' button pressing vigor in a context where information (underlying an RPE) about future average reward was provided well before the average reward itself. Despite no instrumental consequence, participants' pressing force increased for greater current average reward, consistent with a form of Pavlovian effect on motivational vigor. We recorded participants' brain activity during task performance with fMRI. Greater average reward was associated with enhanced activity in dopaminergic midbrain to a degree that correlated with the relationship between average reward and pressing vigor. Interestingly, an opposite pattern was observed in subgenual cingulate cortex, a region implicated in negative mood and motivational inhibition. These findings highlight a crucial role for dopaminergic midbrain in representing aspects of average reward and motivational vigor.
Archive Staff Only
 |
View Item |
