Crossmodal interactions without visual awareness

Binocular rivalry is a form of perceptual bistability in which each monocular image is temporarily removed from visual awareness in favour of the other. I will  present psychophysical evidence investigating crossmodal interactions between touch, audition and vision during binocular rivalry. We show that haptic signals interfere with the dynamics of binocular rivalry outside of visual awareness, that is, by rescuing the congruent visual stimulus from binocular rivalry suppression. This crossmodal interaction occurs both for active exploration and passive tactile stimulation, is strictly tuned for matched visuohaptic spatial frequencies and orientations and depends on temporal and spatial proximity between visual and haptic stimuli. Moreover, haptic stimulation reduces binocular rivalry suppression depth by 45%. These results point to an early crossmodal interaction site, possibly V1. Finally, we show that auditory and tactile rhythms combine to synchronize vision during binocular rivalry suggesting the existence of a supramodal temporal binding mechanism.