Source localization of deviance detection and regularity encoding in the auditory brain
[eng] Our auditory system is continuously encoding acoustic regularities and comparing them with incoming sensory inputs. Novel sounds or acoustic changes must be detected fast in an automatic and unconscious fashion, thus allowing for the reallocation of attentional resources and the proper adjustm...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/102966 |
| Acceso en línea: | https://hdl.handle.net/2445/102966 http://hdl.handle.net/10803/396286 |
| Access Level: | acceso abierto |
| Palabra clave: | Acústica Camps magnètics Percepció auditiva Acoustics Magnetic fields Auditory perception |
| Sumario: | [eng] Our auditory system is continuously encoding acoustic regularities and comparing them with incoming sensory inputs. Novel sounds or acoustic changes must be detected fast in an automatic and unconscious fashion, thus allowing for the reallocation of attentional resources and the proper adjustment of our behaviour. The present thesis encloses three studies that employ Magnetoencephalography and source localization of auditory evoked fields as generated in oddball paradigms to assess the neural correlates of deviance detection and regularity encoding in early stages of the human auditory system. The first study, conducted at the Cognitive Neuroscience Research Group (University of Barcelona), shows distinct neuronal generators involved in the encoding of novel sounds in early and late time intervals; as respectively indexed by Middle Latency-Responses (MLR) evoked between 20 and 50 milliseconds after sound onset, and the later Mismatch component (MMN) generated between 100 and 250 milliseconds. The second study, conducted at the Institut fur Biomagnetismus & Biosignalanalys (University of Munster), shows that deviant acoustic features involving different levels of complexity are processed in distinct time ranges and generated in separated neuronal sources, thus suggesting a hierarchical organization of deviance detection and regularity encoding. The third study, conducted in the Cognitive Neuroscience Research Group using a roving-standard paradigm, indicates that neural repetition-related suppression and repetition enhancement underlie auditory memory trace formation, and that neural generators involved in this process are located in both auditory and non-auditory high-order regions. In sum, results from this thesis suggest that auditory perception is based on a hierarchically organized sensory system whose goal is to predict future events on the basis of previously encoded regularities. |
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