Touch-contingent visual motion perception: tactile events drive visual motion perception.

It has recently been demonstrated that the brain rapidly forms an association between concurrently presented sound sequences and visual motion. Once this association has been formed, the associated sound sequence can drive visual motion perception. This phenomenon is known as "sound-contingent visual motion perception" (SCVM). In the present study, we addressed the possibility of a similar association involving touch instead of audition. In a 9-min exposure session, two circles placed side by side were alternately presented to produce apparent motion in a horizontal direction. The onsets of the circle presentations were synchronized with vibrotactile stimulation on two different positions of the forearm. We then quantified pre- and post-exposure perceptual changes using a motion-nulling procedure. Results showed that after prolonged exposure to visuotactile stimuli, the tactile sequence influenced visual motion perception. Notably, this effect was specific to the previously exposed visual field, thus ruling out the possibility of simple response bias. These findings suggest that SCVM-like associations occur, at least to some extent, for the other modality combinations. Furthermore, the effect did not occur when the forearm posture was changed between the exposure and test phases, suggesting that the association is formed after integrating proprioceptive information.