| Summary: | 碩士 === 國立臺灣大學 === 心理學研究所 === 101 === Past studies have found the thematic relation, which held together by external relations, unifying scenes or events, can speed up semantic processing in either children or adults. However, few studies examine developmental changes and control semantic association to observe the process of thematic relations. Therefore, this thesis is designed to examine the neural correlates of the thematic effect and the developmental differences in processing thematic relations. A cross-modal semantic judgment task was used in functional magnetic resonance imaging (fMRI). Eighteen children and eighteen adults participated in this study. They were asked to determine whether a written character and a subsequent spoken character were related in meaning in an MRI scanner. The character pairs were divided into strong (e.g., ship - port) and weak (e.g., money - tax) thematic relations. The behavioral results showed a thematic effect in adults but not in children. The imaging results showed greater activation in left anterior MTG for the weak as compared to the strong thematic relation in adults. Greater activation in the MTG may suggest a greater demand on integrating thematic features. Moreover, developmental increases in activation were found in left anterior MTG and right thalamus for the weak as compared to the strong thematic relation. In comparison with children, greater MTG activation in adults suggests that they may efficiently integrate and associate thematic related information. Greater thalamus activation in adults suggests a greater regulating mechanism to the cortical regions that decrease the threshold of the competing homophones of the auditory stimulus.
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