title: The role of left inferior frontal gyrus in explicit and implicit semantic processing.
abstract: Using event-related functional MRI, we examined the involvement of the left inferior frontal gyrus (LIFG) in explicit and implicit semantic processing of Chinese sentences. During scanning, Chinese readers read individually presented normal sentences with a contextually expected or unexpected target noun and were asked to perform an explicit or implicit semantic task (semantic or syntactic violation judgment). The conjunction analysis of the two tasks revealed LIFG as the critical brain region for semantic integration. Further, a cross-task comparison showed more extensive activations for the expectancy effect in the explicit task than in the implicit task in regions including bilateral anterior cingulate cortex/dorsolateral prefrontal cortex, left middle temporal gyrus, and right inferior frontal gyrus. These results indicate that LIFG is responsible for the integration process per se and that other brain regions observed in previous studies using explicit semantic tasks may be due to task-induced generic processes (e.g., cognitive control).
authors.affiliation: Department of Psychology, South China Normal University, Guangzhou, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.forename: Zude
authors.initials: Z
authors.lastname: Zhu
authors.forename: John X
authors.initials: JX
authors.lastname: Zhang
authors.forename: Mingxiang
authors.initials: M
authors.lastname: Wu
authors.forename: Hsuan-Chih
authors.initials: HC
authors.lastname: Chen
authors.forename: Suiping
authors.initials: S
authors.lastname: Wang
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D008037:Linguistics; D008279:Magnetic Resonance Imaging; D008297:Male; D008606:Mental Processes; D012660:Semantics; D055815:Young Adult