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Interhemispheric switching mediates perceptual rivalry
1Vision, Touch and Hearing Research Centre, Department of Physiology and Pharmacology, The University of Queensland, Brisbane, 4072, Australia. s.miller@vthrc.uq.edu.au
Current Biology : CB
|February 7, 2001
Summary
Perceptual rivalry, like binocular rivalry, is mediated by interhemispheric switching between brain hemispheres, not within them. This finding impacts understanding consciousness and bipolar disorder.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Perception
Background:
- Binocular rivalry involves alternating perceptions when images from both eyes conflict.
- Previous research suggested rivalry might occur early in the visual pathway.
- Studies in monkeys indicated neural activity higher in the visual pathway correlates with reported perception.
Purpose of the Study:
- To investigate whether unilateral brain hemisphere activation or disruption influences binocular rivalry.
- To explore the role of interhemispheric communication in perceptual alternations.
Main Methods:
- Unilateral caloric vestibular stimulation in human subjects.
- Transcranial magnetic stimulation (TMS) timed to specific phases of perceptual switches.
- Assessment of effects on binocular rivalry and Necker cube perception.
Main Results:
- Unilateral caloric vestibular stimulation altered the time spent in each competing perceptual state.
- TMS disrupted perceptual alternations when applied at specific switch phases.
- Hemispheric activation by caloric stimulation also affected Necker cube alternations.
Conclusions:
- Interhemispheric switching, rather than within-hemisphere processes, mediates perceptual rivalry.
- Competition for awareness in binocular rivalry and reversible figures occurs between hemispheres.
- This interhemispheric switch hypothesis has implications for consciousness and bipolar disorder.