隠喩理解過程の神経基盤 : fMRIによる検討

metaphor

日本認知科学会

In this study, we investigated the neural substrate involved in the comprehension of novel metaphoric sentences using event-related functional magnetic resonance imaging (fMRI). Stimuli were simple and short Japanese copula sentences of the form "An A is a B" without any contextual information. Participants read these sentences silently and responded as to whether or not they could understand the sentence as a metaphor. The metaphoric sentences in contrast to literal sentences elicited the higher activation in the right inferior frontal gyrus (BA 47), the medial frontal gyrus (BA 10), the left inferior frontal gyrus (BA 45), the left precentral, and the left superior temporal gyrus (BA 38). The opposite contrast (literal sentences in contrast to metaphoric sentences) gave higher activation in the left middle frontal gyrus (BA 6), the left fusiform, the insula, the precuneus, the right superior frontal gyrus (BA 6), and the right precentral (BA 4/6). The higher activation in the right inferior frontal gyrus (BA 47) in metaphoric sentences in contrast to literal sentences revealed the involvement in the right hemisphere in metaphor comprehension. These results suggest that figurative statements strongly require cognitive processing for searching semantic relationships compared to literal statements and the right hemisphere is involved in this processing.