Although the orbitofrontal cortex (OFC) has long been considered to play an important role in value computation and decision-making, recent neuroanatomical and functional imaging findings from both animal and human studies suggest there is a heterogeneous functional organization and distributed neural representations of values found in the OFC. Unfortunately, these functional patterns are not easily examined with conventional BOLD signal analyses. Examining the underlying activation patterns of the OFC in value processing has been one of important directions in cognitive neuroscience.
Working with international collaborators from the University of Cambridge and University of Minnesota, Drs. YAN Chao and CHAN Raymond from the Institute of Psychology have adopted the representational similarity analysis (RSA) to specifically examine whether the multi-voxel functional imaging patterns in the OFC associated with value processing during the anticipatory and the consummatory phases of monetary rewards in healthy volunteers. The RSA is one of the newly developed techniques that can overcome limitation of the conventional BOLD signal analyses.
They recruited 23 healthy individuals to undertake the monetary incentive delay task inside the scanner. Their findings showed that despite the conventional BOLD signal analyses did not show any changes of the OFC in responding to gain and loss of monetary rewards, the RSA results demonstrated the OFC encoded magnitude and valence information but not outcome during reward consummation. In particular, these findings were only found in the lateral OFC when encoding the loss information. On the other hand, it is noteworthy that there was similar encoding pattern found between the OFC and the subcortical regions such as the ventral striatum and anterior insular during the reward anticipation regardless of motivated response. Similar pattern was also demonstrated between the OFC, the medial prefrontal cortex, and ventral striatum during reward consummation. Taken together, this study bridges the gap of knowledge in understanding the role of the OFC in value processing during monetary reward anticipation and consummation. This study demonstrates clearly the underling fine-grained functional imaging patterns of the OFC associating with both the valence and magnitude information in monetary reward consummation. These findings implicate the understanding of the altered hedonic processing and value computation observed in patients with neuropsychiatric disorders.
This study was supported by a grant from the Strategic Priority Research Program (B) of the Chinese Academy of Sciences, the National Natural Science Foundation of China, the Beijing Training Project for Leading Talents in Science and Technology, and the Beijing Municipal Science and Technology Commission Grant.