Visual enhancement of touch in spatial body representation
Perception of our own bodies is based on integration of visual and tactile inputs, notably by neurons in the brain's parietal lobes. Here we report a behavioural consequence of this integration process. Simply viewing the arm can speed up reactions to an invisible tactile stimulus on the arm. We observed this visual enhancement effect only when a tactile task required spatial computation within a topographic map of the body surface and the judgements made were close to the limits of performance. This effect of viewing the body surface was absent or reversed in tasks that either did not require a spatial computation or in which judgements were well above performance limits. We consider possible mechanisms by which vision may influence tactile processing.
KeywordsSomatosensory cortex Cross-modal Somatotopic Touch Body representation
This work was supported by grants from the Medical Research Council (UK), the Wellcome Trust and the Leverhulme Trust. We thank John Christie for advice.
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