Spatial sensory organization around the body: anisotropy of audio-tactile integration
Résumé
Body-space interactions are exemplified by the distance-dependent representations of sensory inputs. The processing of multisensory stimuli is facilitated when they are located close to the body, which was demonstrated with tactile and looming auditory stimuli (Canzoneri et al. 2012). The distance of the moving sound source modulates behavioral measures in terms of tactile detection, with tactile detection becoming faster with the auditory stimulus distance to the body becoming smaller. However, little is known about the link between the functional divisions of space and the distance-dependent representations of sensory input.
The present study was based on an extension of the audio-tactile paradigm described in Hobeika et al. (2020) to examine spatial sensory organization all around the body. Healthy right-handed participants had to detect as fast as possible a tactile stimulus delivered on their right hand, while hearing looming sounds coming from the four quadrants of space around the body. The auditory stimuli were burst trains of white noise that were processed through binaural rendering so that the virtual sound sources were looming toward participants from the frontal or rear hemifield and either from the left or from the right hemispace. We examined how, depending of their origin, these auditory looming stimuli interacted with the tactile stimulus’ detection.
Audio-tactile interactions were influenced by the portion of space from which the auditory looming stimulus came. Detection times were shorter when auditory stimuli were looming from the frontal right space, while sound coming from other portions of space did elicit similar behaviors.