A causal account of the brain network computations underlying strategic social behavior

The authors show that transcranial magnetic disruption of the right temporoparietal junction decreases strategic behavior during competitive interactions. The altered behavior relates to neural activity changes both locally and in interconnected prefrontal areas. These brain networks may causally underlie the ability to predict the behavior of other agents. During competitive interactions, humans have to estimate the impact of their own actions on their opponent's strategy. Here we provide evidence that neural computations in the right temporoparietal junction (rTPJ) and interconnected structures are causally involved in this process. By combining inhibitory continuous theta-burst transcranial magnetic stimulation with model-based functional MRI, we show that disrupting neural excitability in the rTPJ reduces behavioral and neural indices of mentalizing-related computations, as well as functional connectivity of the rTPJ with ventral and dorsal parts of the medial prefrontal cortex. These results provide a causal demonstration that neural computations instantiated in the rTPJ are neurobiological prerequisites for the ability to integrate opponent beliefs into strategic choice, through system-level interaction within the valuation and mentalizing networks.