title: Modality-independent neural mechanisms for novel phonetic processing.
abstract: The present study investigates whether the inferior frontal gyrus is activated for phonetic segmentation of both speech and sign. Early adult second language learners of Spanish and American Sign Language at the very beginning of instruction were tested on their ability to classify lexical items in each language based on their phonetic categories (i.e., initial segments or location parameter, respectively). Conjunction analyses indicated that left-lateralized inferior frontal gyrus (IFG), superior parietal lobule (SPL), and precuneus were activated for both languages. Common activation in the left IFG suggests a modality-independent mechanism for phonetic segmentation. Additionally, common activation in parietal regions suggests spatial preprocessing of audiovisual and manuovisual information for subsequent frontal recoding and mapping. Taken together, we propose that this frontoparietal network is involved in domain-general segmentation of either acoustic or visual signal that is important to novel phonetic segmentation.
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University; Program in Cognitive Science, Indiana University, United States; Speech and Hearing Sciences, Indiana University, United States. Electronic address: willjota@indiana.edu.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Williams
authors.affiliation: Program in Cognitive Science, Indiana University, United States; Second Language Studies, Indiana University, United States.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Darcy
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University; Program in Cognitive Science, Indiana University, United States; Program in Neuroscience, Indiana University, United States.
authors.forename: Sharlene D
authors.initials: SD
authors.lastname: Newman
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001921:Brain / Q000502:physiology*; D005260:Female; D006801:Humans; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010700:Phonetics; D010775:Photic Stimulation; D012813:Sign Language; D013061:Speech Acoustics; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
keywords: American Sign Language; Amodality; Audiovisual Speech; IFG; Phonetic processing