Baess, Pamela:Processing of self-initiated sounds: Evidence from EEG studies
- new book 2010, ISBN: 3865834124
Internationaler Buchtitel. In englischer Sprache. Verlag: Leipziger Universitätsvlg, 178 Seiten, zahlreiche z.T. farbige Abbildungen, L=240mm, B=172mm, H=25mm, Gew.=333gr, [GR: 15390 - HC… More...
Internationaler Buchtitel. In englischer Sprache. Verlag: Leipziger Universitätsvlg, 178 Seiten, zahlreiche z.T. farbige Abbildungen, L=240mm, B=172mm, H=25mm, Gew.=333gr, [GR: 15390 - HC/Psychologie/Sonstiges], [SW: - Elektroenzephalographie - EEG], Kartoniert/Broschiert, Klappentext: The goal of the dissertation was to investigate the processing of self-initiated sounds in comparison with externally-initiated sounds. An internal prediction mechanism was suggested to enable the discrimination of sounds from different origin (self-initiated vs. externally-initiated). Probably, the correct identification of self-initiated sounds is reached by recruiting an efference copy of the motor command and sensory feedback loops. Previous studies reported attenuated N1 or N1m components for the self-initiated sounds in contrast to the processing of external sounds. Less is known about the features of the underlying mechanism itself. The present thesis suggests three features, namely specificity, adaptivity and predictability. They are assumed to be crucial for the internal prediction mechanism to fulfil its supposed function. These three features were investigated differently in five EEG studies. In all experiments the participants were asked to press a button, an action that caused the presentation of a sound. In another condition, these sounds were replayed within the same stimulus parameters. In Experiment 1, unpredictable sounds in regard to both the sound quality and the time of presentation were used. It was examined whether the internal prediction mechanism could still operate under conditions of uncertainties when the exact sound and the time of sound presentation after the button press were unknown. Attenuated N1 responses for self-initiated sounds were reported even in unpredictable situations. Experiment 2 addressed the question of whether the reported attenuations were selectively coupled with the act of self-initiation. Therefore, an auditory stream was presented that contained the self-initiated and externally-initiated sounds. As our results showed, only the self-initiated sounds were attenuated, not the externally-initiated ones. In Experiment 3, the influence of foreknowledge on the stimulus timing was investigated. In this study, the participants received a tactile cue signalling the presentation of the sounds. Our results clearly revealed attenuated N1 responses for self-initiated sounds although the participants were informed of the impending sounds. In previous studies, a different processing between self-initiated and externally initiated sounds was observed around 100 ms after sound onset. The focus of Experiment 4 was the middle latency responses indicating an early auditory processing. Self-initiated sounds were even attenuated in the middle latency responses, starting as early as 35 ms after stimulus onset. In Experiment 5, unexpected sounds instead of expected ones occurred after the self-initiated button press. Even when the expectation of a particular sound was violated, the N1 reduction for self-initiated sounds was clearly evident. In summary, this thesis showed that the processing of the internal prediction mechanism is indeed specific, adaptive and predictive. Therefore, the mechanism enables the accurate discrimination between the sensory consequences of one's own selfgenerated actions and externally-initiated ones. The goal of the dissertation was to investigate the processing of self-initiated sounds in comparison with externally-initiated sounds. An internal prediction mechanism was suggested to enable the discrimination of sounds from different origin (self-initiated vs. externally-initiated). Probably, the correct identification of self-initiated sounds is reached by recruiting an efference copy of the motor command and sensory feedback loops. Previous studies reported attenuated N1 or N1m components for the self-initiated sounds in contrast to the processing of external sounds. Less is known about the features of the underlying mechanism itself. The present thesis suggests three features, namely specificity, adaptivity and predictability. They are assumed to be crucial for the internal prediction mechanism to fulfil its supposed function. These three features were investigated differently in five EEG studies. In all experiments the participants were asked to press a button, an action that caused the presentation of a sound. In another condition, these sounds were replayed within the same stimulus parameters.
In Experiment 1, unpredictable sounds in regard to both the sound quality and the time of presentation were used. It was examined whether the internal prediction mechanism could still operate under conditions of uncertainties when the exact sound and the time of sound presentation after the button press were unknown. Attenuated N1 responses for self-initiated sounds were reported even in unpredictable situations. Experiment 2 addressed the question of whether the reported attenuations were selectively coupled with the act of self-initiation. Therefore, an auditory stream was presented that contained the self-initiated and externally-initiated sounds. As our results showed, only the self-initiated sounds were attenuated, not the externally-initiated ones. In Experiment 3, the influence of foreknowledge on the stimulus timing was investigated. In this study, the participants received a tactile cue signalling the presentation of the sounds. Our results clearly revealed attenuated N1 responses for self-initiated sounds although the participants were informed of the impending sounds.
In previous studies, a different processing between self-initiated and externally initiated sounds was observed around 100 ms after sound onset. The focus of Experiment 4 was the middle latency responses indicating an early auditory processing. Self-initiated sounds were even attenuated in the middle latency responses, starting as early as 35 ms after stimulus onset. In Experiment 5, unexpected sounds instead of expected ones occurred after the self-initiated button press. Even when the expectation of a particular sound was violated, the N1 reduction for self-initiated sounds was clearly evident.
In summary, this thesis showed that the processing of the internal prediction mechanism is indeed specific, adaptive and predictive. Therefore, the mechanism enables the accurate discrimination between the sensory consequences of one's own selfgenerated actions and externally-initiated ones.<
