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Abstract:
Cellular recording in non-human primates has revealed neurons
responsive to both visual and tactile stimulation whose visual
receptive fields depend on where the hand is located. We sought to
investigate whether human covert spatial attention is influenced by
body-part-centered spatial frameworks. We have previously shown
that processing of fingertip tactile information can depend on
variations in body posture, including intermanual distance and
cranial orientation relative to hand location (Driver &
Grossenbacher, 1996). We now report cuing experiments in which a
spatially nonpredictive tactile cue precedes a visual target.
Visual detection response time data show that uninformative
fingertip stimulation can automatically attract visual attention
towards it. Similar to findings from unimodal visual cuing studies,
exogenous tactile cuing produces a short-lived effect: at cuing
intervals of a few hundred msec, visual processing is more
efficient on the cued side compared to the uncued side.
Manipulation of hand separation and visual eccentricity allowed us
to test for effects of the relative position of stimulated hand and
visual target. The pattern of cuing effects indicates that visual
attention is distributed according to an anatomically weighted
density function, consistent with visual selection operating within
body-part-centered spatial frameworks.
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