Noninformative Vision Causes Adaptive Changes in Tactile Sensitivity

The last few years have witnessed a rapid growth of research investigating how information is integrated across sensory modalities, a process at the core of our everyday perceptual experiences. The present study focuses on the integration of vision and touch and, in particular, how tactile perception is affected by a view of the relevant body part containing no information about the tactile stimulus itself. Previous studies have established that this "noninformative vision" can improve subsequent tactile discrimination (Kennett et al., 2001; Taylor-Clarke et al., 2004a), a finding we confirm in the present study. However, we also report here that noninformative vision impairs the detection of tactile stimuli and the discrimination of near-threshold stimuli. These effects are shown to resemble, and indeed combine additively with, shifts in discrimination and detection thresholds produced by adaptation to suprathreshold tactile stimulation. We conclude that noninformative vision of the body does not simply enhance somatosensory processing, but rather it induces adaptive changes in tactile sensitivity via shifts in gain control operating within a bimodal sensory system. This constitutes a novel means by which vision of the body can alter tactile perception.