No rightward shift in spatial attention after cueing visuotactile prediction in the peripersonal space of the hands.

Abstract

It is proposed that stimuli in the peripersonal space (PPS) of the hands (the space directly surrounding the hands) are processed multimodally to be able to act upon those stimuli and thereby protect bodily integrity. The present study aims to test the concept of multimodal processing in the PPS as a predictive visuotactile mechanism. It was expected that cueing a predictive visuotactile relationship in one hand, but not the other, would cause the attention to shift to the validly cued hand. The cueing experiment consisted of a visual stimulus appearing in the PPS of the hands, and was in 80% of the cases followed by a tactile stimulus when appearing in the right hand PPS, but was never followed by a tactile stimulus when appearing in the left-hand PPS. Thirty healthy participants were tested, using a pre-intervention and post-intervention Temporal Order Judgment task to measure cueing effects. The experiment did show a shift of spatial attention towards the validly cued right hand, but this shift occurred in both the experimental (cued) and the control group (who performed a backwards counting experiment instead of the cueing experiment) and thus cannot be attributed to the cueing experiment. An additional pre-intervention and post-intervention pointing task did not show the rightward shift in perceived body midline that was expected.