Repetitive TMS of the temporo-parietal junction disrupts participant's expectations in a spontaneous Theory of Mind task

A recent debate about Theory of Mind (ToM) concerns whether spontaneous and explicit mentalizing are based on the same mechanisms. However, only a few neuroimaging studies have investigated the neural bases of spontaneous ToM, with inconsistent results. The present study had two goals: first, to investigate whether the right Temporo-Parietal Junction (rTPJ) is crucially involved in spontaneous ToM and second, to gain insight into the role of the rTPJ in ToM. For the first time, we applied rTMS to the rTPJ while participants were engaged in a spontaneous false belief task. Participants watched videos of a scene including an agent who acquires a true or false belief about the location of an object. At the end of the movie, participants reacted to the presence of the object. Results show that, during stimulation of the control site, RTs were affected by both the participant's expectations and the belief of the agent. Stimulation of the rTPJ significantly modulated task performance, supporting the idea that spontaneous ToM, as well as explicit ToM, relies on TPJ activity. However, we did not observe a disruption of the representation of the agent's belief. Rather, the stimulation interfered with participant's predictions, supporting the idea that rTPJ is crucially involved in self-other distinction.