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Differential effects of the temporal and spatial distribution of audiovisual stimuli on cross‐modal spatial recalibration
Author(s) -
Bruns Patrick,
Dinse Hubert R.,
Röder Brigitte
Publication year - 2020
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.14779
Subject(s) - stimulus (psychology) , psychology , auditory stimuli , perception , spatial frequency , audiology , auditory perception , stimulation , visual perception , communication , cognitive psychology , neuroscience , physics , medicine , optics
Visual input constantly recalibrates auditory spatial representations. Exposure to isochronous audiovisual stimuli with a fixed spatial disparity typically results in a subsequent auditory localization bias (ventriloquism aftereffect, VAE), whereas exposure to spatially congruent audiovisual stimuli improves subsequent auditory localization (multisensory enhancement, ME). Here, we tested whether cross‐modal recalibration is affected by the stimulation rate and/or the distribution of audiovisual spatial disparities during training. Auditory localization was tested before and after participants were exposed either to audiovisual stimuli with a constant spatial disparity of 13.5° (VAE) or to spatially congruent audiovisual stimulation (ME). In a between‐subjects design, audiovisual stimuli were presented either at a low frequency of 2 Hz, as used in previous studies of VAE and ME, or intermittently at a high frequency of 10 Hz, which mimics long‐term potentiation (LTP) protocols and which was found superior in eliciting unisensory perceptual learning. Compared to low‐frequency stimulation, VAE was reduced after high‐frequency stimulation, whereas ME occurred regardless of the stimulation protocol. In two additional groups, we manipulated the spatial distribution of audiovisual stimuli in the low‐frequency condition. Stimuli were presented with varying audiovisual disparities centered around 13.5° (VAE) or 0° (ME). Both VAE and ME were equally strong compared to a fixed spatial relationship of 13.5° or 0°, respectively. Taken together, our results suggest (a) that VAE and ME represent partly dissociable forms of learning and (b) that auditory representations adjust to the overall stimulus statistics rather than to a specific audiovisual spatial relationship.