Meyer
Fakultäten » Philosophische Fakultät » Psychologisches Institut » Neuropsychologie » Prof. Dr. Lutz Jäncke » Meyer
Completed research project
| Title / Titel | Rapid and slow temporal information processing and speech perception | ||||
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| Abstract (PDF, 14 KB) | |||||
| Summary / Zusammenfassung | Background: The classical brain-language model derived from the work of Broca, Wernicke, and Lichtheim which favors the existence of ‘speech centres’ in the left hemisphere has been becoming more and more controversial. It has rather turned out that the role the right hemisphere plays in speech comprehension has been unwarrantedly ignored. Recent models of speech comprehension describe both the left and the right hemisphere as governing signal analysis during auditory language processing 1-4 with the left hemisphere preferentially extracting rapid information from short integration windows while the right hemisphere is better adept at extracting slow information from long integration windows. Here, we aim to run a series of fMRI and TMS studies to test the models’ predictions by investigating phonetic and prosodic modulations. Working hypothesis: The human auditory system is essential for human communication. Relative to visual information processing audition is more reliant on encoding and decoding information in the temporal domain. Present neurocognitive models of speech perception more strongly consider this issue and attempt particularly define how auditory cortex accomplishs the comprehensive deciphering of temporally encoded speech information. Recent neuroanatomic evidence speaks to the issue of a fine-grained parcellation of the auditory system5,6 with Heschl’s gyrus primarily subserving the early stages of auditory processing while the posterior peri-sylvian regions mediate the complex acoustic processes during speech and nonspeech perception. By means of the studies delineated below we will be elucidating to what extent complex auditory functions are lateralised. Furthermore we plan to investigate the role of fronto-opercular regions during slow and rapid auditory processing since these regions have recently been characterised as potentially mediating effort-related processes rather than auditory perception per se. Specific aims: This project is specifically meant to investigate the neural underpinnings of functional lateralisation in speech perception. Brain responses in the left and right peri-auditory regions to auditory speech and nonspeech stimuli (indexed by functional magnetic resonance imaging, fMRI) are assumed to vary systematically as a function of fast and slow acoustic modulations comprised in the acoustic signal. We derive our predictions from a recent model which proposes a differential recruitment of left and right temporal areas during speech perception2. The fMRI/TMS studies outlined in the following aim at uncovering the basic processing principles in the auditory domain which form the basis for the interplay between rapid phonological and slow prosodic modulations during speech processing. Part I (Experiment 1-4) of this project we will be addressing the issue of rapid temporal processing within short time windows. The proposed studies seek to elucidate to what extent rapid temporal processing may form the base of left hemispheric lateralisation for speech. In part II (Experiment 5-7) of this project we will be focusing on slow temporal modulations which might be essential for a proper understanding of sentence prosody and its interaction with sentence meaning. Prosody might be characterised as the ‘melody of speech’ comprising a pattern of pitch, intensity, and timing over the course of a larger domain such as phrases, sentences, or utterances. Both segmental and suprasegmental features constitute prosody. FMRI research in the auditory domain is still a methodological challenge as the quality of stimulus presentation confounds with ambient scanner noise and may negatively affect the perception quality. However, our group successfully has taken explicit actions to improve the adverse scanning environment and to achieve an optimal level of auditory presentation (see 2.3.1) |
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| Publications / Publikationen | Meyer, M., Zaehle, T., Gountouna, V. E., Barron, A., Jancke, L., & Turk, A. (2005). Spectro-temporal processing during speech perception involves left posterior auditory cortex. Neuroreport, 16(18), 1985-1989.Zaehle, T., Wustenberg, T., Meyer, M., & Jancke, L. (2004). Evidence for rapid auditory perception as the foundation of speech processing: a sparse temporal sampling fMRI study. Eur J Neurosci, 20(9), 2447-2456. | ||||
| Keywords / Suchbegriffe | auditory cortex, temporal perception, language perception | ||||
| Project leadership and contacts / Projektleitung und Kontakte |
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| Funding source(s) / Unterstützt durch |
SNF (Personen- und Projektförderung) |
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| Duration of Project / Projektdauer | Jan 2005 to Dec 2007 |