Touch Interacts with Vision during Binocular Rivalry with a Tight Orientation Tuning

Abstract

Multisensory integration is a common feature of the mammalian brain that allows it to deal more efficiently with the ambiguity of sensory input by combining complementary signals from several sensory sources. Growing evidence suggests that multisensory interactions can occur as early as primary sensory cortices. Here we present incompatible visual signals (orthogonal gratings) to each eye to create visual competition between monocular inputs in primary visual cortex where binocular combination would normally take place. The incompatibility prevents binocular fusion and triggers an ambiguous perceptual response in which the two images are perceived one at a time in an irregular alternation. One key function of multisensory integration is to minimize perceptual ambiguity by exploiting cross-sensory congruence. We show that a haptic signal matching one of the visual alternatives helps disambiguate visual perception during binocular rivalry by both prolonging the dominance period of the congruent visual stimulus and by shortening its suppression period. Importantly, this interaction is strictly tuned for orientation, with a mismatch as small as 7.5° between visual and haptic orientations sufficient to annul the interaction. These results indicate important conclusions: first, that vision and touch interact at early levels of visual processing where interocular conflicts are first detected and orientation tunings are narrow, and second, that haptic input can influence visual signals outside of visual awareness, bringing a stimulus made invisible by binocular rivalry suppression back to awareness sooner than would occur without congruent haptic input.

Cross-modal associations between vision, touch, and audition influence visual search through top-down attention, not bottom-up capture

“…The fact that we did not find any evidence for automatic capture with tactile cues contrasts with previous studies that have suggested that touch influences visual processing in early sensory areas (Lunghi & Alais, 2013;Lunghi et al, 2010). Lunghi and Alais showed that exploration of a tactile grating produced prolonged dominance and reduced suppression of a grating of matching orientation during binocular rivalry.…”

“…Another key difference between our experiments and that of Lunghi et al (2010;Lunghi & Alais, 2013) is the level of complexity in the display. Lunghi et al and Lunghi and Alais presented only one visual item, whereas the experiments reported here used an array of visual items.…”

“…Lunghi and Alais showed that exploration of a tactile grating produced prolonged dominance and reduced suppression of a grating of matching orientation during binocular rivalry. This effect was tuned for both orientation and spatial frequency (Lunghi & Alais, 2013), suggesting that it occurred through interactions in early visual areas that are selective for these features. This is in contrast to the dependence on voluntary goal-directed behavior found in this report, which suggests higher-level processes.…”

“…Furthermore, there is behavioral evidence for the influence of tactile inputs on visual perception. Exploration of a tactile grating has been shown to produce prolonged dominance and reduced suppression of a visual grating of matched orientation and spatial frequency during binocular rivalry (Lunghi & Alais, 2013;Lunghi, Binda, & Morrone, 2010). Given these strong links, we also test the effects of tactile cues on search for matched visual spatial frequencies.…”

Melodic sound enhances visual awareness of congruent musical notes, but only if you can read music

“…Rivalry offers a way to study the inferential nature of perception when the brain is confronted with conflicting sensory evidence (11,12). Within this context, recent studies imply that rivalry dynamics are governed by influences related to the likelihood of competing perceptual interpretations, such as motor actions (13), affective connotation (14)(15)(16), familiarity (17), and concomitant sensory input from other modalities (18)(19)(20). Here we examined the limits of susceptibility of rivalry to predictive influences by asking whether binocular rivalry dynamics depend on multisensory congruence between abstract representations familiar to individuals with expertise in that domain of abstraction.…”