Dual routes for verbal repetition: Articulation-based and acoustic–phonetic codes for pseudoword and word repetition, respectively

• Published in: Brain and language Vol. 122; no. 1; pp. 1 - 10
• Main Authors: Yoo, Sejin, Chung, Jun-Young, Jeon, Hyeon-Ae, Lee, Kyoung-Min, Kim, Young-Bo, Cho, Zang-Hee
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.07.2012; Elsevier
• Subjects: Acoustic Stimulation; Acoustics; Adolescent; Adult; Articulation (Speech); Audition–articulation interface; Auditory Perception; Auditory Stimuli; Biological and medical sciences; Brain - physiology; Brain Hemisphere Functions; Brain Mapping; Diagnostic Tests; Dual-stream model; Female; Fundamental and applied biological sciences. Psychology; Humans; Image Processing, Computer-Assisted; Imitative Behavior - physiology; Imitative learning; Language; Language Processing; Learning - physiology; Magnetic Resonance Imaging; Male; Observational Learning; Phonetics; Production and perception of spoken language; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Speech - physiology; Speech perception; Speech Perception - physiology; Speech production; Verbal repetition; Vocabulary Development; Vowels; Imitative learning; Speech production; Dual-stream model; Verbal repetition; Audition–articulation interface; Speech perception; Human; Speech articulation; Word; Cognition; Verbal perception; Audition-articulation interface; Verbal production; Experimental study; Learning; Hearing; Acquisition process; Language; Imitation; Phonetics; Speech; Models; Repetition
• ISSN: 0093-934X; 1090-2155
• DOI: 10.1016/j.bandl.2012.04.011

[Display omitted] ► We compared verbal repetitions of ambiguous auditory stimuli by fMRI. ► We separately localized neural activities involved in each phase of verbal-repetition task. ► We observed the frontal-versus-temporoparietal dissociation between pseudoword- and word-perceived stimuli. ► The result supports the dual-stream model of speech processing and the imitative learning of vocabulary. Speech production is inextricably linked to speech perception, yet they are usually investigated in isolation. In this study, we employed a verbal-repetition task to identify the neural substrates of speech processing with two ends active simultaneously using functional MRI. Subjects verbally repeated auditory stimuli containing an ambiguous vowel sound that could be perceived as either a word or a pseudoword depending on the interpretation of the vowel. We found verbal repetition commonly activated the audition–articulation interface bilaterally at Sylvian fissures and superior temporal sulci. Contrasting word-versus-pseudoword trials revealed neural activities unique to word repetition in the left posterior middle temporal areas and activities unique to pseudoword repetition in the left inferior frontal gyrus. These findings imply that the tasks are carried out using different speech codes: an articulation-based code of pseudowords and an acoustic–phonetic code of words. It also supports the dual-stream model and imitative learning of vocabulary.