Postural modulation of visual-tactile integration in the neglected space
Poster Presentation

Angelo Maravita
Dipartimento di Psicologia, Università degli Studi di Milano-Bicocca, Milano, Italy

Sabrina Longhi
Dipartimento di Psicologia, Università degli Studi di Milano-Bicocca, Milano, Italy

Charles Spence
Department of Experimental Psychology, University of Oxford, UK

Francesco Pavani
Dipartimento di Scienze della Cognizione e della Formazione, Università di Trento, Rovereto, Italy

     Abstract ID Number: 144
     Full text: PDF
     Last modified: June 27, 2005

Abstract
Both egocentric and body-centred frame of references are likely to determine visual-tactile integration. In this work we explore how crossmodal interference is affected by an impairment of contralesional egocentric space representation as that shown by patients with unilateral neglect.
A modified version of the Crossmodal Congruency Paradigm was used, in which unattended visual distractor produce large crossmodal interference on the localization of tactile targets, as shown by previous research.
In three experimental groups, namely right brain-damaged patients with and without neglect and normal observers, tactile stimuli were delivered to the right hand, while visual distractors were presented at fixation. The right hand adopted one of four different postures (10 or 50° to the ipsi- or contralesional side) in separate blocks of trials. Normal observers and patients without neglect showed stronger interference at 10 than 50° in both hemifields, due to the well-known effect of spatial proximity on crossmodal interference. Neglect patients showed the same trend for ipsilesionale space but an opposite trend for contralesional space, with stronger interference at 50 than 10°.
These results suggest that an altered representation of contralesional space in egocentric coordinates, due to neglect, may significantly alter crossmodal visual-tactile interference in that space.