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.:COVER 1
BIBLIOGRAPHISCHE BESCHREIBUNG 2
ACKNOWLEDGEMENTS 3
CONTENTS 4
CHAPTER 1: Introduction 6
C1.1: Stability and uncertainty in perception 6
C1.2: Auditory, visual and audio-visual multistability 14
C1.3: Capturing the subjective perceptual experience 25
C1.4: Limitations of preceding studies, objectives, and outline of the Thesis 33
CHAPTER 2: Study 1 “Pupillometry in auditory multistability” 36
C2.1.1 Experiment 1: Introduction 36
C2.1.2 Experiment 1: Material and Methods 38
C2.1.3 Experiment 1: Data analysis 44
C2.1.4 Experiment 1: Results 48
C2.1.5 Experiment 1: Discussion 52
C2.2.1 Experiment 2: Introduction 54
C2.2.2 Experiment 2: Material and Methods 54
C2.2.3 Experiment 2: Data analysis 56
C2.2.4 Experiment 2: Results 57
C2.3 Experiment 1 & 2: Discussion 61
C2.4 Supplement Study 1 65
CHAPTER 3: Study 2 “Multimodal moment-by-moment coupling in perceptual bistability” 71
C3.1.1 Experiment 1: Introduction 71
C3.1.2 Experiment 1: Results 74
C3.1.3 Experiment 1: Discussion 80
C3.1.4 Experiment 1: Material and Methods 84
C3.1.5 Experiment 1: Data analysis 87
C3.2 Supplement Study 2 92
CHAPTER 4: Study 3 “Boundaries of bimodal coupling in perceptual bistability” 93
C4.1.1 Experiment 1: Introduction 93
C4.1.2 Experiment 1: Material and Methods 98
C4.1.3 Experiment 1: Data analysis 102
C4.1.4 Experiment 1: Results 108
C4.1.5 Experiment 1: Discussion 114
C4.2.1 Experiment 2: Introduction 116
C4.2.2 Experiment 2: Material and Methods 119
C4.2.3 Experiment 2: Data analysis 125
C4.2.4 Experiment 2: Results 133
C4.3 Experiment 1 & 2: Discussion 144
C4.4 Supplement Study 3 151
CHAPTER 5: General Discussion 154
C5.1 Significance for models of multistability and implications for the perceptual architecture 162
C5.2 Recommendations for future research 166
C5.3 Conclusion 168
REFERENCES 170
APPENDIX 186
A1: List of Figures 186
A2: List of Tables 188
A3: List of Abbreviations and Symbols 189
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:74901 |
| Date | 25 May 2021 |
| Creators | Grenzebach, Jan |
| Contributors | Bendixen, Alexandra, Einhäuser-Treyer, Wolfgang, Technische Universität Chemnitz |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 10.5281/zenodo.4769210 |
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