Does the medial orbitofrontal cortex have a role in social valuation?
Noonan MP., Sallet J., Rudebeck PH., Buckley MJ., Rushworth MF.
It has been claimed that social behaviour changes after lesions of the ventromedial prefrontal cortex (vmPFC). However, lesions in humans are rarely restricted to a well defined cortical area. Although vmPFC lesions usually include medial orbitofrontal cortex (mOFC), they typically also affect subgenual and/or perigenual anterior cingulate cortex. The purpose of the current study is to investigate the role of mOFC in social valuation and decision-making. We tested four macaque monkeys prior to and after focal lesions of mOFC. Comparison of the animals' pre- and postoperative performance revealed that, unlike lesions of anterior cingulate gyrus (ACCg), lesions of mOFC did not induce alterations in social valuation. MOFC lesions did, however, induce mild impairments in a probabilistic two-choice decision task, which were not seen after ACCg lesions. In summary, the double dissociation between the patterns of impairment suggest that vmPFC involvement in both decision-making and social valuation may be mediated by distinct subregions centred on mOFC and ACCg respectively.