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Causal role of vTPJ and lATL in social-semantic working memory: Insights from TMS
Poster Session D, Saturday, October 26, 10:30 am - 12:00 pm, Great Hall 3 and 4
Nan Lin1, Weiting Shi1, Baishen Liang1, Wanying Zhao1; 1The Institute of Psychology of the Chinese Academy of Sciences
Introduction Recently, it has been proposed that the left ventral temporoparietal junction (vTPJ) and lateral anterior temporal lobe (lATL) underlie social-semantic working memory, demonstrated by their heightened activation to sentences with social meaning compared to word lists, as well as their persistent social-semantic-selective activity after the stimuli disappeared (Zhang et al., 2023). However, there is still a lack of consensus on this hypothesis. This study aimed to examine the hypothesis using transcranial magnetic stimulation (TMS), which induces a transient ‘virtual lesion’ by disrupting normal firing patterns, thus providing causal links between targeted brain regions and behavior that imaging techniques cannot offer. Methods In Experiment 1, continuous theta-burst stimulation (cTBS) was administered to four sites, including the vTPJ, lATL, posterior superior temporal sulcus (pSTS), and vertex. The pSTS, implicated in general sentence processing, and the vertex, presumed to be non-contributory to cognitive tasks, served as control sites. Immediate recall performance was examined across four categories of stimuli: social sentences, non-social sentences, social word lists, and non-social word lists. In Experiment 2, online TMS was used to selectively suppress activity in the vTPJ and vertex during stimulus maintenance, to assess the impact on subsequent recall of the same types of stimuli. Results In Experiment 1, inhibition of the vTPJ or lATL (but not pSTS) significantly impaired the recall of social sentences compared to non-social sentences, a distinction not observed with word lists. These results support the social semantic working memory hypothesis proposed by Zhang et al. (2023). Additionally, inhibition of the vTPJ or lATL (and the pSTS) resulted in a greater impairment in sentence recall compared to word-list recall, even when only non-social stimuli were considered. This indicates that these regions contribute to sentence processing beyond the social semantic domain. Furthermore, Experiment 2, which specifically interrupted the stimulus maintenance stage, revealed similar suppression effects in the vTPJ, providing clearer evidence for its role in working memory function. Conclusion Our findings provide causal evidence for the involvement of the vTPJ and lATL in social semantic working memory, with a particular emphasis on the vTPJ. Furthermore, TMS-induced suppression in these regions also affected non-social sentence recall, suggesting a broader spectrum of cognitive functions than previously indicated by the activation patterns in Zhang et al. (2023). This highlights the importance of employing diverse methodological approaches to comprehensively evaluate the functional roles of specific brain regions.
Topic Areas: Meaning: Lexical Semantics, Meaning: Discourse and Pragmatics