Effects of numeric magnitude on the cortical valuation network

Previous work has identified a distributed, network of neural systems involved in appraising the value of rewards, such as when winning $100. We hypothesized that involvement of intraparietal sulcus (IPS) in this network is specialized for processing numeric rather than monetary value. To test our hypothesis, we manipulated numeric magnitude and units to construct a range of economic rewards (e.g., +$1, +100¢) in response to simple decisions. Consistent with our hypothesis, BOLD activity in IPS was related to changes in numeric magnitude, independent of monetary value, whereas activity in OFC was associated with monetary value, independent of numeric magnitude. Finally, by using representation similarity analysis, we found that the information represented in IPS and OFC was more consistent with the patterns expected if representations of numeric magnitudes or monetary values, respectively, were in a compressive scale. Together, these findings show the importance of numerical cognition for understanding how the brain processes monetary rewards.