[Purpose] The interaction between the visual and tactile modalities influences on different levels from neural activity, perception, higher cognition to behavior. The aim of this study was to examine how a visual stimulus influences tactile sensitivity depending on temporal asynchrony. [Subjects and Methods] In total, 15 participants took part in this study. They were required to perform a two-alternative forced-choice task regarding whether a tactile pulse was felt. The individual participants' tactile thresholds were estimated using a repetitive stepwise method. Visual stimuli were simultaneously presented with various temporal gaps (0 ms, ± 50 ms, ± 100 ms, and ± 300 ms), whereas no visual stimulus was presented in the tactile only condition. The tactile thresholds in eight conditions were compared using analysis of variance. [Results] Of the participants, 53.5% showed the most sensitive tactile threshold when presented with a visual stimulus with a short temporal gap, especially when the visual stimulus preceded the tactile one by 50 ms. [Conclusion] The preceding visual stimulus facilitates the perceptual sensitivity of the tactile sensation. Providing sensory stimuli in a multisensory mode benefits perceptual encoding. A pre-attentional mechanism led by a particular sensory modality might work as a perceptual advantage for another modality.
Keywords: Multisensory integration; Stimulus onset asynchrony; Tactile sensitivity.