Poster D36, Friday, August 17, 4:45 – 6:30 pm, Room 2000AB

Fine subdivisions of the left anterior temporal lobe in semantic processing of social words

Xiaosha Wang1, Bijun Wang1, Yanchao Bi1;1Beijing Normal University

Recent neuroimaging studies consistently reported selective involvement of the anterior temporal lobes (ATLs) in conceptual processing of social words, i.e. words describing social behaviors of animate (social) entities. One potential factor that has been systematically confounded in this finding is emotional valence, given that social words tend to be associated with emotional feelings. It is thus unclear whether the ATLs are sensitive to sociality, emotional valence, or both. We investigated these effects in the ATLs using a 2 (social/nonsocial) × 2 (valenced/neutral) factorial design in an fMRI study, with words such as “honor” (S+V+), “duty” (S+V-), “miracle” (S-V+), “content” (S-V-). Two distinct subregions within the left ATL were identified to be sensitive to either sociality or valence without interaction between these two factors. Semantic judgment of social words evoked stronger activation than nonsocial words in the left anterior superior temporal sulcus (aSTS), regardless of whether social words are valenced or neutral (S+V+ & S+V- > S-V+ & S-V-); valenced words evoked stronger activation than neutral words in the left temporal pole (S+V+ & S-V+ > S+V- & S-V-); these two factors showed little interaction in the ATL at the group level. These social or valence-sensitive clusters were distinct from the left anterior superior temporal gyrus cluster that exhibited a general “abstractness” effect (all four abstract conditions > concrete object words), since the abstractness cluster showed little social and valence effects. These subregions exhibited distinct whole-brain functional connectivity patterns during the resting state, with the social aSTS synchronized with key regions in social cognition, the valence cluster with the left amygdala and the abstractness cluster with the perisylvian language regions. These results indicate that the way in which the left ATL supports semantic processing is highly fine grained, including at least dissociable neural substrates that support dimensions of social interaction, valence, and abstractness.

Topic Area: Meaning: Lexical Semantics