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Brain Mechanisms Underlying the Reading of Mandarin Derivational Morpheme
Poster D19 in Poster Session D, Saturday, October 26, 10:30 am - 12:00 pm, Great Hall 4
Chun-Hsien Hsu1, Ting-Hsin Yen1; 1National Central University
The present study aims to explore the neural mechanisms underlying the processing of different morpheme types—suffixes and quasi-suffixes—during the reading of Chinese disyllabic words. Specifically, true suffixes are highly grammaticalized morphemes that typically attach to the end of a word to modify its grammatical category or function. For example, the suffix 頭 /tóu/ can denote something that is at the head or top. 頭 /tóu/ can be used to create nouns, as in 石頭 /shítou/ (stone). Quasi-suffixes, on the other hand, are partially grammaticalized morphemes that still retain more of their original lexical meaning compared to true suffixes. For example, 場 /chǎng/ can function as a suffix indicating "place" or "field," and it retains its original meanings in compounds, as in 市場 /shìchǎng/ (market). A lexical decision experiment was conducted to address whether quasi-suffixes, which are less grammatically conventionalized than true suffixes, elicit different patterns of neural activity, particularly in brain regions associated with semantic ambiguity and syntactic structure formation. Twelve native Chinese speakers participated in the experiment, in which they were required to determine whether visually presented disyllabic words were real Chinese words or pseudowords. The target stimuli were thirty disyllabic words with a suffix as the second morpheme and thirty disyllabic words with a quasi-suffix as the second morpheme. Target words were selected by matching lexical parameters between the two types of words, including word frequency, frequency of the first character, frequency of the second character, number of meanings of the first character, number of meanings of the second character, number of senses of the first character, number of senses of the second character, semantic transparency between the first character and the word, and the semantic transparency between the second character and the word. During this task, magnetoencephalography (MEG) were recorded with a 156 channel axial-gradiometer system. The source analysis of MEG data revealed distinct neural activity patterns associated with the reading of suffixed and quasi-suffixed words. Specifically, the reading of quasi-suffixed words generated greater brain activity compared to suffixed words in the left pars orbitalis and the left temporal cortex. These regions have been previously implicated in semantic ambiguity and syntactic structure formation, respectively. The observed larger brain activity for quasi-suffixes suggests that quasi-suffix constructions are more complex in both syntax and semantics due to their less conventionalized grammatical status. The findings of this study support the hypothesis of the grammaticalization of affixes, suggesting that suffix morphemes undergo semantic bleaching, resulting in reduced neural activity in regions associated with semantic and syntactic processing. Additionally, these results demonstrate the neural basis of morphological complexity. Specifically, the results indicate that the left inferior frontal and left temporal cortices are sensitive to morphological complexity in the reading of Chinese words, highlighting the role of these brain regions in managing different types of orthographic systems during visual word recognition.
Topic Areas: Morphology, Meaning: Lexical Semantics