Do you what I am saying? : electrophysiological dynamics of visual speech processing and the role of orofacial effectors for cross-modal predictions
| dc.contributor.advisor | López Hernández, Vladimir | |
| dc.contributor.author | Michon Desbiey, Maëva | |
| dc.contributor.other | Pontificia Universidad Católica de Chile. Escuela de Psicología | |
| dc.date.accessioned | 2019-11-04T14:39:34Z | |
| dc.date.available | 2019-11-04T14:39:34Z | |
| dc.date.issued | 2019 | |
| dc.description | Tesis (Doctor en Psicología)--Pontificia Universidad Católica de Chile, 2019 | |
| dc.description.abstract | The need of a comprehensive model to account for the neurobiology of language has quite a long history. New empirical data have challenged classical models. A new framework is needed to foster our understanding of brain mechanisms underlying speech perception and production. In this dissertation, we postulate the existence of a trimodal network for speech perception that emphasizes the importance of visual processing of speech related orofacial movements and its representation in motor cortices. In that sense, we hypothesize that auditory (phonemes), visual (visemes) and motor (articulemes) aspects of speech are bonded in a trimodal repertoire. In order to test our hypothesis, we recorded EEG signal while participants were attentively observing different type of linguistic and non-linguistic orofacial movements in two conditions: under normal observation and observation holding a speech effector depressor horizontally between their teeth. ERPs analyses of the signal provide evidence of cross-modal predictions indexed by the N270 and the N400-like components. The amplitude of these components was specifically modulated by the visual salience of visual speech cues; the more salient the more predictable. Interestingly, when orofacial effectors were restricted, the amplitude of N400 was significantly reduced, suggesting that language production system is recruited for predictions. The time-frequency analysis, on the other hand, demonstrated the involvement of motor cortices for visual speech perception. More specifically, a significant difference in the µ-suppression was observed between linguistic and nolinguistic orofacial movements. The power of the µ-suppression was modulated by visual salience but diminished for the more salient visual speech cues when the participants orofacial effectors were blocked. The results reported in this dissertation represent preliminary evidence of the existence of the proposed trimodal network and, in particular, of the articuleme. Undoubtedly, further research using complementary neuroimaging techniques are required to better understand this multimodal interplay during language perception and production. | |
| dc.format.extent | 113 páginas | |
| dc.identifier.doi | 10.7764/tesisUC/PSI/26875 | |
| dc.identifier.uri | https://doi.org/10.7764/tesisUC/PSI/26875 | |
| dc.identifier.uri | https://repositorio.uc.cl/handle/11534/26875 | |
| dc.language.iso | es | |
| dc.nota.acceso | Contenido completo | |
| dc.rights | acceso abierto | |
| dc.subject.ddc | 400 | |
| dc.subject.dewey | Lenguas | es_ES |
| dc.subject.other | Percepción visual | es_ES |
| dc.subject.other | Percepción auditiva | es_ES |
| dc.title | Do you what I am saying? : electrophysiological dynamics of visual speech processing and the role of orofacial effectors for cross-modal predictions | es_ES |
| dc.type | tesis doctoral | |
| sipa.codpersvinculados | 1002510 |