Tactile interference in visually guided reach-to-grasp movements.

This study addresses the issue of cross-modal links in goal-directed actions and specifically the influence of non-relevant tactile information on visually guided reach-to-grasp movements. Right-handed participants reached for and grasped with either their left or right hand a visually presented, midsagitally placed target. The target was presented alone, or was accompanied by an unseen, tactile distractor placed in the non-reaching hand. The tactile distractor was either smaller than, the same size as or larger than the target. Significant alterations in kinematic parameterisation were restricted to the grasp component of the movement, and specifically to the reaching right hand. More importantly, the size of the unseen tactile distractors in the left hand altered the grasp parameterisation of the right hand. These findings are discussed in the context of current theories of the control of action by perceptual processes.