title: Linguistic category structure influences early auditory processing: Converging evidence from mismatch responses and cortical oscillations.
abstract: While previous research has established that language-specific knowledge influences early auditory processing, it is still controversial as to what aspects of speech sound representations determine early speech perception. Here, we propose that early processing primarily depends on information propagated top-down from abstractly represented speech sound categories. In particular, we assume that mid-vowels (as in 'bet') exert less top-down effects than the high-vowels (as in 'bit') because of their less specific (default) tongue height position as compared to either high- or low-vowels (as in 'bat'). We tested this assumption in a magnetoencephalography (MEG) study where we contrasted mid- and high-vowels, as well as the low- and high-vowels in a passive oddball paradigm. Overall, significant differences between deviants and standards indexed reliable mismatch negativity (MMN) responses between 200 and 300ms post-stimulus onset. MMN amplitudes differed in the mid/high-vowel contrasts and were significantly reduced when a mid-vowel standard was followed by a high-vowel deviant, extending previous findings. Furthermore, mid-vowel standards showed reduced oscillatory power in the pre-stimulus beta-frequency band (18-26Hz), compared to high-vowel standards. We take this as converging evidence for linguistic category structure to exert top-down influences on auditory processing. The findings are interpreted within the linguistic model of underspecification and the neuropsychological predictive coding framework.
authors.affiliation: Department of Language and Literature, Max Planck Institute for Empirical Aesthetics, Frankfurt, Germany; Department of Linguistics, University of Maryland, College Park, MD, USA; Biological incl. Cognitive Psychology, Institute for Psychology, University of Leipzig, Germany. Electronic address: mathias.scharinger@aesthetics.mpg.de.
authors.forename: Mathias
authors.initials: M
authors.lastname: Scharinger
authors.affiliation: Centre for French and Linguistics, University of Toronto Scarborough, Canada; Department of Linguistics, University of Toronto, Canada.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Monahan
authors.affiliation: Department of Linguistics, University of Maryland, College Park, MD, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Idsardi
mesh_terms: D000161:Acoustic Stimulation; D001921:Brain / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D006801:Humans; D008037:Linguistics; D015225:Magnetoencephalography; D008297:Male; D012815:Signal Processing, Computer-Assisted; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
keywords: Beta-band power; Cortical oscillations; MEG; Mismatch negativity; Predictive coding; Speech sound perception; Underspecification