Abstract
To efficiently interact with the external environment, our nervous system combines information arising from different sensory modalities. Recent evidence suggests that cross-modal interactions can be automatic and even unconscious, reflecting the ecological relevance of cross-modal processing. Here, we use continuous flash suppression (CFS) to directly investigate whether haptic signals can interact with visual signals outside of visual awareness. We measured suppression durations of visual gratings rendered invisible by CFS either during visual stimulation alone or during visuo-haptic stimulation. We found that active exploration of a haptic grating congruent in orientation with the suppressed visual grating reduced suppression durations both compared with visual-only stimulation and to incongruent visuo-haptic stimulation. We also found that the facilitatory effect of touch on visual suppression disappeared when the visual and haptic gratings were mismatched in either spatial frequency or orientation. Together, these results demonstrate that congruent touch can accelerate the rise to consciousness of a suppressed visual stimulus and that this unconscious cross-modal interaction depends on visuo-haptic congruency. Furthermore, since CFS suppression is thought to occur early in visual cortical processing, our data reinforce the evidence suggesting that visuo-haptic interactions can occur at the earliest stages of cortical processing.
Highlights
Combining information arising from different sensory modalities is essential to interact efficiently with the environment (Alais, Newell, & Mamassian, 2010)
We investigated the effect of haptic stimulation on interocular suppression times combining continuous flash suppression (CFS), in which dynamic Mondrian maskers presented to one eye suppress a visual grating in the other, with active exploration of a haptic grating congruent or incongruent in orientation with the visual grating
Neither of the touch conditions differed from each other or from the no-touch condition. This indicates that the effect of congruent touch on reducing CFS suppression durations is selective for both orientation and spatial frequency
Summary
Combining information arising from different sensory modalities is essential to interact efficiently with the environment (Alais, Newell, & Mamassian, 2010). It has been shown that during binocular rivalry, unambiguous haptic stimulation promotes dominance of the congruent visual stimulus independently of awareness: touch prolongs dominance durations of the congruent visual stimulus and is able to rescue it from suppression, making it visible (Lunghi et al, 2010) This cross-modal interaction is highly specific and relies on the objective congruency in spatial frequency (Lunghi et al, 2010), orientation (Lunghi & Alais, 2013), and spatial proximity (Lunghi & Morrone, 2013) between the visual image and the tactile stimulus. On the basis of the results obtained in binocular rivalry paradigms, we anticipate that haptic gratings, when congruent with orientation and spatial frequency of the visual grating, will decrease the suppression duration of the visual grating
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
