Task-dependent increases and decreases of BOLD signal in theory of mind brain regions during strategic social interaction.

Theory of Mind (ToM) is known as the capacity to infer others' thoughts, intentions, and emotions, supported by a distributed neural brain network, including the medial prefrontal cortex (mPFC), temporoparietal junction (TPJ), inferior frontal gyrus (IFG), and precuneus. Although the Rock-Paper-Scissors (RPS) game is used to study the cognitive ToM domain, previous fMRI studies had methodological limitations, including lack of appropriate control conditions and the absence of analyses addressing the directionality of BOLD signal changes. The present fMRI study employed a modified RPS paradigm designed to overcome these limitations. Forty-six healthy adults performed the RPS game and a control task. Whole-brain analyses contrasted neural activity and task-modulated functional connectivity (TMFC) between these conditions and examined BOLD signal changes relative to baseline. In contrast to prior findings of BOLD signal suppression below baseline in affective ToM tasks, RPS elicited increased BOLD responses in canonical ToM regions, including the mPFC, bilateral TPJ, IFG, and precuneus, as well as additional frontal, cingulate and visual regions. TMFC analyses converged with these findings, demonstrating increased RPS-related functional interactions between the bilateral TPJ and precuneus with the left IFG, and between the mPFC and the right TPJ with the right IFG. Additionally, greater deactivation (negative BOLD deflection) below baseline during RPS was observed in the midcingulate cortex and opercular regions bilaterally. These findings extend current understanding of ToM network functioning by demonstrating that the engagement of its affective and cognitive domains manifest through TMFC changes and directionally distinct neural responses.