title: The left posterior superior temporal gyrus participates specifically in accessing lexical phonology.
abstract: Impairments in phonological processing have been associated with damage to the region of the left posterior superior temporal gyrus (pSTG), but the extent to which this area supports phonological processing, independent of semantic processing, is less clear. We used repetition priming and neural repetition suppression during functional magnetic resonance imaging (fMRI) in an auditory pseudoword repetition task as a semantics-free model of lexical (whole-word) phonological access. Across six repetitions, we observed repetition priming in terms of decreased reaction time and repetition suppression in terms of reduced neural activity. An additional analysis aimed at sublexical phonology did not show significant effects in the areas where repetition suppression was observed. To test if these areas were relevant to real word production, we performed a conjunction analysis with data from a separate fMRI experiment which manipulated word frequency (a putative index of lexical phonological access) in picture naming. The left pSTG demonstrated significant effects independently in both experiments, suggesting that this area participates specifically in accessing lexical phonology.
authors.affiliation: Medical College of Wisconsin, Neuro Lab, Milwaukee, WI 53226, USA. wgraves@mcw.edu
authors.forename: William W
authors.initials: WW
authors.lastname: Graves
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Grabowski
authors.forename: Sonya
authors.initials: S
authors.lastname: Mehta
authors.forename: Prahlad
authors.initials: P
authors.lastname: Gupta
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010700:Phonetics; D011930:Reaction Time / Q000502:physiology; D012660:Semantics; D013702:Temporal Lobe / Q000098:blood supply / Q000502:physiology*
chemical_list: D010100:Oxygen