By employing a within-subjects design for the Control and Other tasks, the present study provides, to our knowledge, the first direct evidence that vmPFC is the area in which representations of reward prediction error are shared between the self and the simulated-other. Subjects used the sRPE to learn the other’s hidden variable and the vmPFC was the only brain region with BOLD signals that were significantly modulated by both the subject’s reward prediction error in the Control task and the subject’s sRPE

in the Other task. Moreover, our findings also provide direct evidence that the same vmPFC region is critical for the subject’s decisions, whether or not the other’s process was simulated. In both tasks, vmPFC signals were significantly modulated by the subject’s decision variable Selleck LY294002 (the subject’s reward probability) at the time their decisions were made. Mentalizing by direct recruitment requires the same neural circuitry for shared representations between the self and the simulated-other. Even apart from direct recruitment, shared representations between the self and the other are considered to play an important role in other forms of social cognition, such as empathy. Our

findings, with specific roles described for making and learning value-based decisions, indicate that vmPFC belongs to areas for shared representations in various cognitive domains (Decety and Sommerville, 2003, Keysers and Gazzola, 2007, Mobbs et al., 2009, Rizzolatti and Sinigaglia, 2010 and Singer et al., PDK4 2004). For encoding learning signals, the vmPFC is likely more adaptive than the ventral striatum. In contrast LEE011 to the vmPFC signals, signals in the ventral striatum were significantly modulated only by

the subject’s own reward prediction error in the Control task (Figure S3; Table 2). The vmPFC was preferentially recruited to simulate the other’s process in this study, concordant with the general notion that the vmPFC may encode signals related to reward prediction error when internal models are involved (O’Doherty et al., 2007). The vmPFC may be more sensitive to task demands. During the Other task, no area was significantly modulated by the subject’s own reward prediction error. This might be simply due to a limitation in the task design, as the fixed reward size for subjects might have limited detection of reward prediction error. Another aspect, however, is that the subject’s own reward prediction error was not as useful as the sRPE for learning to predict the other’s choices in this task. Also, the vmPFC may be specifically recruited when subjects used the other’s outcomes for learning, as in the Other task, rather than when they vicariously appreciated the other’s outcomes. The activity in the ventral striatum might be evoked only when the other’s outcomes are more “personal” to subjects (Moll et al., 2006), e.g.