Influence of target trajectory on auditory peripersonal space threshold estimations for sound sources approaching or receding in discrete steps

ESTEBAN N. LOMBERA; NICOLÁS D. RODRIGUEZ ALTIERI; IGNACIO SPIOUSAS; PABLO E. ETCHEMENDY; RAMIRO O. VERGARA

Villa Carloz Paz

Congreso; XXXIV Reunión Anual SAN 2019; 2019

Sociedad Argentina de Neurociencias

To effectively navigate and interact with their environment, humans need to integrate information on the position of the body and on the space around the body (peripersonal space, PPS). The PPS is often described as having a single, distance-based, dichotomic boundary within which stimuli elicit enhanced neural and behavioral responses. However, recent studies have shown that PPS-related measures are not binary and that boundaries can shrink or expand as a function of the properties of the stimulus, including factors not related to the actual stimulus position. One of such factors is the stimulus trajectory. It has been reported that the PPS expands or shrinks depending on whether the auditory stimulus is approaching the body or receding from it, respectively. As far as we know, all of the previous studies that reported such modulations used sources with continuous movement. In this study, we aim to determine if this effect can be elicited by sound sources moving in discrete steps, a kind of trajectory that we consider more ecologically valid. By measuring the reachability to a sound source, we found an overestimation of the auditory PPS threshold when sources approached the listeners. In contrast, when the sources were receding or describing random trajectories, the PPS threshold was in close accordance with the participant?s static reach.