Development of a Japanese version of a theory-of-mind functional localizer for functional magnetic resonance imaging

Theory-of-mind (ToM) has been extensively studied using neuroimaging, with the goal of finding a neural basis for ToM and its associate emotional and cognitive processes. In neuroimaging, a functional localizer is used when a region of interest needs to be identified in a way that is statistically independent of the main experiment. The original ToM localizer (ToM-L) for functional magnetic resonance imaging (Dodell-Feder et al., 2011) measures brain activity when a set of English sentences and related questions are read and answered by participants. We developed a linguistically localized version of the ToM-L for use with Japanese speakers, and evaluated it by scanning 70 participants. The results showed that this localizer could be used to define individual ToM-related areas, requiring about one-third of the scanning time of the original ToM-L while maintaining its statistical ability to identify individual ToM-related brain regions.