Qiong Ma, Sachiko Kiyama, Michiru Makuuchi
Language has referential and emotive uses. Referential language depicts events and can be verified or falsified by comparison with the event, whereas emotive language lacks the events upon which one can determine the truth value of the sentence. Using functional magnetic resonance imaging (fMRI), we investigated the brain mechanisms of the processing of the two semantically distinct forms of language in a paradigm of empathy for pain conveyed through single short sentences. In the emotive condition, subjective expressions of pain, such as "I have a toothache", were used. In the referential condition, an objective description of events in which an individual would experience pain, such as "I cut my finger", were presented. Assuming each stimulus elicits activation proportional to pain intensity ratings, we combined referential and emotive conditions and performed an analysis with a parametric modulation model. It revealed activation in the anterior cingulate cortex and, slightly below the threshold, the anterior insula, that are involved in the perception of one's own pain. Without pooling the two conditions, only the referential condition yielded activation in the two regions. Crucially, although both emotive and referential language activated multiple regions, emotive sentences activated the right temporoparietal junction, whereas referential sentences activated the precuneus/retrosplenial cortex, parahippocampal cortex, and the language network in the left hemisphere. These results suggest that a complementary interhemispheric network supports the processing of both types of language.