Poster F124, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
Magnifying the view of the hand changes its cortical representation. A Transcranial magnetic stimulation study.
Elisabetta Ambron1, Nicole White1, Jared Medina2, Branch Coslett1; 1Laboratory for Cognition and Neural Stimulation, Dept. of Neurology, Perelman School of Medicine at the University of Pennsylvania, 2Department of Psychology, University of Delaware.
Changes in the perceived size of a body part, like the hand, using magnifying glasses influence pain and tactile perception, and motor functions. If the beneficial effect of the magnification of the hand in task performance has been reported in different domains, the mechanisms by which this effect occurs are still little understood. One possible interpretation is that the visual magnification of hand increases the cortical excitability (Experiment 1) and the cortical area devoted to the body part in question (Experiment 2). We measured motor evoked potentials (MEP) from the first dorsal interosseus (FDI) when participants were looking at their hand in normal or magnified vision. In Experiment 1, TMS was applied over the FDI area (hotspot), while in Experiment 2, a 3x5 grid of stimulation sites was superimposed over the hotspot and TMS was applied over these 15 sites. MEP amplitude increased with the magnification of the hand at the hot spot (Experiment 1) and in the areas surrounding the hotspot (Experiment 2). These evidence suggest that the magnification effect might be due to a rapid remapping of the cortical representation of hand.
Topic Area: PERCEPTION & ACTION: Multisensory