Eintrag in der Universitätsbibliographie der TU Chemnitz
Volltext zugänglich unter
URN: urn:nbn:de:bsz:ch1-qucosa2-749013
Grenzebach, Jan
Bendixen, Alexandra ; Einhäuser-Treyer, Wolfgang (Gutachter)
Cross-modal mechanisms: perceptual multistability in audition and vision
Modalitäts-übergreifende Mechanismen: Perzeptuelle Multistabilität beim Hören und Sehen
Kurzfassung in englisch
Perceptual multistability is a phenomenon that is mostly studied in all modalities separately. The phenomenon reveals fundamental principles of the perceptual system in the formation of an emerging cognitive representation in the consciousness. The momentary perceptual organizations evoked during the stimulation with ambiguous stimuli switches between several perceptual organizations or percepts: The auditory streaming stimulus in audition and the moving plaids stimulus in vision, elicit different at least two percepts that dominate awareness exclusively for a random phase or dominance duration before an inevitable switch to another percept occurs. The similarity in the perceptual experience has led to propose a global mechanism contributing to the perceptual multistability phenomena crossmodally. Contrary, the difference in the perceptual experience has led to propose a distributed mechanism that is modality-specific. The development of a hybrid model has synergized both approaches. We accumulate empirical evidence for the contribution of a global mechanism, albeit distributed mechanisms play an indispensable role in this cross-modal interplay. The overt report of the perceptual experience in our experiments is accompanied by the recording of objective, cognitive markers of the consciousness: Reflexive movements of the eyes, namely the dilation of the pupil and the optokinetic nystagmus, correlate with the unobservable perceptual switches and perceptual states respectively and have their neuronal rooting in the brainstem. We complement earlier findings on the sensitivity of the pupil to visual multistability: It was shown in two independent experiments that the pupil dilates at the time of reported perceptual switches in auditory multistability. A control condition on confounding effects from the reporting process confines the results. Endogenous, evoked internally by the unchanged stimulus ambiguity, and exogenous, evoked externally by the changes in the physical properties of the stimulus, perceptual switches could be discriminated based on the maximal amplitude of the dilation. The effect of exogenous perceptual has on the pupil were captured in a report and no-report task to detect confounding perceptual effects. In two additional studies, the moment-by-moment coupling and coupling properties of percepts between concurrent multistable processes in audition, evoked by auditory streaming, and in vision, evoked by moving plaids, were found crossmodally. In the last study, the externally induced percept in the visual multistable process was not relayed to the simultaneous auditory multistable process: Still, the observed general coupling is fragile but existent. The requirement for the investigation of a moment-by-moment coupling of the multistable perceptual processes was the application of a no-report paradigm in vision: The visual stimulus evokes an optokinetic nystagmus that has machine learnable different properties when following either of the two percepts. In combination with the manually reported auditory percept, attentional bottlenecks due to a parallel report were circumvented. The two main findings, the dilation of the pupil along reported auditory perceptual switches and the crossmodal coupling of percepts in bimodal audiovisual multistability, speak in favor of a partly global mechanism being involved in control of perceptual multistability; the global mechanism is incarcerated by the, partly independent, distributed competition of percepts on modality level. Potentially, supramodal attention-related modulations consolidate the outcome of locally distributed perceptual competition in all modalities.
| Universität: | Technische Universität Chemnitz | |
| Institut: | Professur Struktur und Funktion kognitiver Systeme | |
| Fakultät: | Fakultät für Naturwissenschaften | |
| Dokumentart: | Dissertation | |
| Betreuer: | Bendixen, Alexandra ; Einhäuser-Treyer, Wolfgang | |
| SWD-Schlagwörter: | Wahrnehmung , Multimodales System , Multistabilität , Pupillometrie , Augenbewegung , Maschinelles Lernen | |
| Freie Schlagwörter (Englisch): | perception , multistability , multimodal , pupil dilation , optokinetic nystagmus , hybrid mechanism , auditory streaming , moving plaids , no-report , support vector machine | |
| DDC-Sachgruppe: | 152.1 | |
| Sprache: | englisch | |
| Tag der mündlichen Prüfung | 04.05.2021 |
