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fNIRS-Guided TMS Distinguishes the Function of the Left ATL and AG in the Semantic Integration of Chinese Compound Words
Poster Session B, Friday, September 12, 4:30 - 6:00 pm, Field House
Wenqi Cai1, Xiangyang Zhang2, Xiaojuan Wang1, Jianfeng Yang1; 1Shaanxi Normal University, 2Xi'an Technological University
Abstract: Lexical semantic integration involves the activation of two crucial regions on the left hemisphere: the left anterior temporal lobe (ATL) and the angular gyrus (AG). The current study investigated their precise function in morpheme-meaning integration by combining the neural correlation (functional near-infrared spectroscopy, fNIRS) and neural causality (transcranial magnetic stimulation, TMS) techniques. The participants performed a lexical decision task after viewing two consecutively presented Chinese characters while their brain activation was recorded using the fNIRS technique. Three types of two-character words were used for two experiments: transparent compounds (e.g., 炽热, hot) with the word meaning that is same to their two characters (both 炽 and 热 mean hot), opaque compounds (e.g., 风流, dissolute) with the word meaning that is different from either the first (风, wind) or the second character (流, flow), and monomorphemic words (e.g., 伶俐, clever) with two characters that are not two independent morphemes. Experiment 1 found a different pattern of results at the left ATL and AG channels. The left ATL showed a morpheme complexity effect that its activation was stronger for two types of compound words than monomorphemic ones, with no difference between transparent and opaque compounds. In contrast, the left AG showed a semantic transparency effect that its activation was stronger for transparent than opaque compounds, with no difference between opaque compounds and monomorphemic words. Experiment 2 further investigated the causal relationship between the activities of the left ATL and AG and their function in the semantic integration of Chinese compound words. Two group participants performed the same task as Experiment 1 after they received a 40-second virtual lesion at the left ATL or the left AG. The results found that the ATL-impaired group showed no activation differences among the three types of words either at the ATL or the AG channels. In contrast, the AG-impaired group showed no difference among three types of words at the ATL channels. As for the AG channels, the activation for two types of compound words was inhibited thus the semantic transparency effect disappeared, and a reversed morpheme complexity effect was observed that the activation for monomorphemic words was stronger than for two types of compound words. These findings suggested a different function of the left ATL and AG for the semantic integration of Chinese compound words. The left ATL likely undertakes domain-general integration processing, while the left AG is specifically involved in domain-specific semantic feature integration. This study finely distinguishes the roles of ATL and AG in the semantic integration of Chinese compound words. Keywords: semantic integration, compound words, semantic transparency, fNIRS, TMS
Topic Areas: Meaning: Lexical Semantics, Morphology