On The Way To Linguistic Representation: Neuromagnetic Evidence of Early Auditory Abstraction in the Perception of Speech and Pitch

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dc.contributor.advisorIdsardi, William Jen_US
dc.contributor.advisorPoeppel, David Een_US
dc.contributor.authorMonahan, Philip Josephen_US
dc.contributor.departmentLinguisticsen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2010-02-19T06:35:00Z
dc.date.available2010-02-19T06:35:00Z
dc.date.issued2009en_US
dc.description.abstractThe goal of this dissertation is to show that even at the earliest (non-invasive) recordable stages of auditory cortical processing, we find evidence that cortex is calculating abstract representations from the acoustic signal. Looking across two distinct domains (inferential pitch perception and vowel normalization), I present evidence demonstrating that the M100, an automatic evoked neuromagnetic component that localizes to primary auditory cortex is sensitive to abstract computations. The M100 typically responds to physical properties of the stimulus in auditory and speech perception and integrates only over the first 25 to 40 ms of stimulus onset, providing a reliable dependent measure that allows us to tap into early stages of auditory cortical processing. In Chapter 2, I briefly present the episodicist position on speech perception and discuss research indicating that the strongest episodicist position is untenable. I then review findings from the mismatch negativity literature, where proposals have been made that the MMN allows access into linguistic representations supported by auditory cortex. Finally, I conclude the Chapter with a discussion of the previous findings on the M100/N1. In Chapter 3, I present neuromagnetic data showing that the re-sponse properties of the M100 are sensitive to the missing fundamental component using well-controlled stimuli. These findings suggest that listeners are reconstructing the inferred pitch by 100 ms after stimulus onset. In Chapter 4, I propose a novel formant ratio algorithm in which the third formant (F3) is the normalizing factor. The goal of formant ratio proposals is to provide an explicit algorithm that successfully "eliminates" speaker-dependent acoustic variation of auditory vowel tokens. Results from two MEG experiments suggest that auditory cortex is sensitive to formant ratios and that the perceptual system shows heightened sensitivity to tokens located in more densely populated regions of the vowel space. In Chapter 5, I report MEG results that suggest early auditory cortical processing is sensitive to violations of a phonological constraint on sound sequencing, suggesting that listeners make highly specific, knowledge-based predictions about rather abstract anticipated properties of the upcoming speech signal and violations of these predictions are evident in early cortical processing.en_US
dc.identifier.urihttp://hdl.handle.net/1903/9823
dc.subject.pqcontrolledLanguage, Linguisticsen_US
dc.subject.pqcontrolledBiology, Neuroscienceen_US
dc.subject.pqcontrolledPsychology, Cognitiveen_US
dc.subject.pquncontrolledCognitive Neuroscienceen_US
dc.subject.pquncontrolledCognitive Scienceen_US
dc.subject.pquncontrolledLinguisticsen_US
dc.subject.pquncontrolledMEGen_US
dc.subject.pquncontrolledPsycholinguisticsen_US
dc.subject.pquncontrolledSpeech Perceptionen_US
dc.titleOn The Way To Linguistic Representation: Neuromagnetic Evidence of Early Auditory Abstraction in the Perception of Speech and Pitchen_US
dc.typeDissertationen_US

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