In order to make decisions between disparate rewards such as when choosing between buying a refrigerator and booking a vacation, it is often suggested that the value of these rewards needs to be encoded on a “common scale or currency” so that it is possible to work out which option is more preferable to that individual.

In this fMRI study, we found partially overlapping value-related activity within ventromedial prefrontal cortex (vmPFC) during anticipation of juice and money reward outcomes, whereas the right anterior insula showed negative correlations as a function of increasing expected reward.

These results indicate that vmPFC and anterior insula contain overlapping representations of anticipatory value, consistent with the existence of a common currency for the value of expected outcomes in these regions. (Kim et al., Cerebral Cortex, 2011)