Visual-tactile interactions in tool-use: Peripersonal space or multisensory spatial attention?
Poster Presentation

Nicholas P Holmes
Experimental Psychology, Oxford University, UK

Charles Spence
Experimental Psychology, Oxford University, UK

Gemma A. Calvert
Psychology, Bath University, UK

     Abstract ID Number: 126
     Full text: PDF
     Last modified: July 11, 2005

Abstract
Active and skilful tool-use has been claimed to extend the visual boundaries of multisensory peripersonal space. In macaque monkeys, it is thought that peripersonal space is represented in the ventral premotor cortex and the ventral intraparietal sulcus, primarily contralaterally to a given body part. Neurons representing peripersonal space show body-part centred visual receptive fields – representing visual stimuli with respect to a particular body part, regardless of the positions of the eyes, head, and of other body parts. This property allows clear predictions to be made regarding how tool-use affects peripersonal space representations in humans: If tool-use extends peripersonal space in humans, then visual stimuli presented at the end of an actively-used tool held in the right hand should always result in larger activations of ‘peripersonal space’ areas in the left hemisphere, regardless of the position of the tool in space (i.e., on the right or on the left). If, on the other hand, the effects of tool-use on visual-tactile interactions are due primarily to multisensory spatial attentional factors, then visual stimuli presented at the tip of a tool should always result in enhanced activations contralateral to the visual stimulus. These hypotheses were tested using functional magnetic resonance imaging