Seeing Digits Modulates Finger Tactile Perception
Poster Presentation

Brozzoli Claudio
INSERM U534 Espace et Action

     Abstract ID Number: 119
     Full text: Not available
     Last modified: March 17, 2006
     Presentation date: 06/19/2006 10:00 AM in Hamilton Building, Foyer
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Abstract
Perceiving numbers involves a spatial component. Neuropsychological and TMS studies provided evidence that subjects use spatial representations, akin to a ‘mental number line’, in basic numerical processing tasks. Merely looking at numbers may modulate visual perception. We asked whether visual number perception may modulate tactile detection, according to number magnitude. Moreover, from the observation that western subjects’ way of counting (1 to 5) is associated on their fingers, we tested whether tactile perception would be affected according to an anatomy/magnitude-based association, or an out-of-the-body spatial representation of number magnitude. Normal participants were asked to detect touches delivered to the little finger of the (unseen) right hand after a brief central presentation of one of four digits (1, 2, 4, 5), with the hand either in a palm-down, or palm-up posture. When the little finger was stimulated in the right hemispace (palm-down), tactile detection performance was better following visual presentation of the largest (5) than smallest number (1); a better performance after the smallest than the largest digit presentation was found in the opposite posture (palm-up). Implications for multisensory body-space number mapping are discussed.