The Role of the Parietal Cortex in the Representation of Task-Reward Associations.
Rewards obtained from specific behaviors can and do change across time. To adapt to such conditions, humans need to represent and update associations between behaviors and their outcomes. Much previous work focused on how rewards affect the processing of specific tasks. However, abstract associations between multiple potential behaviors and multiple rewards are an important basis for adaptation as well. In this experiment, we directly investigated which brain areas represent associations between multiple tasks and rewards, using time-resolved multivariate pattern analysis of functional magnetic resonance imaging data. Importantly, we were able to dissociate neural signals reflecting task-reward associations from those related to task preparation and reward expectation processes, variables that were often correlated in previous research. We hypothesized that brain regions involved in processing tasks and/or rewards will be involved in processing associations between them. Candidate areas included the dorsal anterior cingulate cortex, which is involved in associating simple actions and rewards, and the parietal cortex, which has been shown to represent task rules and action values. Our results indicate that local spatial activation patterns in the inferior parietal cortex indeed represent task-reward associations. Interestingly, the parietal cortex flexibly changes its content of representation within trials. It first represents task-reward associations, later switching to process tasks and rewards directly. These findings highlight the importance of the inferior parietal cortex in associating behaviors with their outcomes and further show that it can flexibly reconfigure its function within single trials. Significance statement: Rewards obtained from specific behaviors rarely remain constant over time. To adapt to changing conditions, humans need to continuously update and represent the current association between behavior and its outcomes. However, little is known about the neural representation of behavior-outcome associations. Here, we used multivariate pattern analysis of functional magnetic resonance imaging data to investigate the neural correlates of such associations. Our results demonstrate that the parietal cortex plays a central role in representing associations between multiple behaviors and their outcomes. They further highlight the flexibility of the parietal cortex, because we find it to adapt its function to changing task demands within trials on relatively short timescales.
Bernstein Center for Computational Neuroscience Berlin, Berlin Center for Advanced Neuroimaging, Collaborative Research Centre SFB 940, Volition and Cognitive Control, Dresden University of Technology, D-01069 Dresden, Germany, david.wisniewski@bccn-berlin.de.
David
http://orcid.org/0000-0003-4793-1171
D
Wisniewski
Psychology Department, University of Milano-Bicocca, I-20126 Milan, Italy, Milan Center for Neuroscience, I-20052 Milan, Italy.
Carlo
C
Reverberi
Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544.
Ida
I
Momennejad
Northwestern University Feinberg School of Medicine, Department of Neurology, Chicago, Illinois 60611, and.
Thorsten
http://orcid.org/0000-0002-3575-2670
T
Kahnt
Bernstein Center for Computational Neuroscience Berlin, Berlin Center for Advanced Neuroimaging, Cluster of Excellence NeuroCure, and Department of Neurology, Charité University Medicine Berlin, D-10117 Berlin, Germany, Collaborative Research Centre SFB 940, Volition and Cognitive Control, Dresden University of Technology, D-01069 Dresden, Germany, Berlin School of Mind and Brain and Department of Psychology, Humboldt University of Berlin, D-10099 Berlin, Germany.
John-Dylan
JD
Haynes
D000328:Adult; D001245:Association Learning; D005260:Female; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000502:physiology*; D012201:Reward
cognitive control; fMRI; multivariate pattern analysis; parietal cortex; reward; task-set