Approaching threat modulates visuotactile interactions in peripersonal space

Abstract

The region surrounding our body (i.e. peripersonal space) is coded in a multimodal representation by fronto-parietal bimodal neurons integrating tactile stimuli on the body with nearby visual stimuli. This has often been suggested to serve a defensive purpose, which we propose could be mediated through visuotactile predictions. An approaching threat would then be of particular interest to peripersonal space processing. To investigate this, we asked participants to respond as fast as possible to a tactile stimulus on the hand, while looking at an animation of an approaching or receding spider or butterfly. Tactile stimulation was applied at one of 25 possible time points during the animation. Tactile reaction times were faster when an approaching stimulus was closer to the hand at the time of tactile presentation. Critically, this effect of distance on reaction times was larger when participants saw an approaching spider compared to an approaching butterfly, but only for participants who were afraid of spiders. This finding demonstrates that the perceived threat of an approaching stimulus modulates visuotactile interactions in peripersonal space and is consistent with the idea that visuotactile predictions are important for defensive purposes and maintaining bodily integrity.

Keywords: Approaching threat; Near space defensive; Peripersonal space; Visuotactile prediction; Visuotactile processing.

Fig. 1

Overview of the experimental set-up. Dimensions are given in the drawing, as well as the positions of the hand, chin rest and foot pedal

Fig. 2

Screenshots of the animations of butterflies and spiders used in the experiment

Fig. 3

Average median reaction times and fitted linear functions. The average median reaction times to approaching and receding spiders and butterflies at all 25 time points for high- (left) and low-fear (right) participants, as well as their fitted linear functions (a) and average slope and intercept parameters for the fitted linear functions (b). Please note that for approaching animations, earlier time points correspond to the stimulus being further way. The error bars represent the within-subject standard deviation