Cross-Modal Training Induces Changes in Spatial Representations Early in the Auditory Processing Pathway

Abstract

In the ventriloquism aftereffect, brief exposure to a consistent spatial disparity between auditory and visual stimuli leads to a subsequent shift in subjective sound localization toward the positions of the visual stimuli. Such rapid adaptive changes probably play an important role in maintaining the coherence of spatial representations across the various sensory systems. In the research reported here, we used event-related potentials (ERPs) to identify the stage in the auditory processing stream that is modulated by audiovisual discrepancy training. Both before and after exposure to synchronous audiovisual stimuli that had a constant spatial disparity of 15°, participants reported the perceived location of brief auditory stimuli that were presented from central and lateral locations. In conjunction with a sound localization shift in the direction of the visual stimuli (the behavioral ventriloquism aftereffect), auditory ERPs as early as 100 ms poststimulus (N100) were systematically modulated by the disparity training. These results suggest that cross-modal learning was mediated by a relatively early stage in the auditory cortical processing stream.

Intersensory binding across space and time: A tutorial review

“…The ventriloquist aftereffect has also been examined in other modalities. Audiotactile ventriloquist aftereffects have been demonstrated by Bruns, Liebnau and Röder (2011a) ;Bruns, Spence and Röder (2011b). They also suggested that auditory space can be rapidly recalibrated to compensate for audiotactile spatial disparities.…”

Psychophysics and neuronal bases of sound localization in humans

“…Ventriloquism effect and aftereffect are illusions that make it possible to study how the spatial information from the two sensory modalities is aligned, what transformations do unimodal representations undergo in this process, and the short-term plasticity that can result from the perceptual alignment process (Bruns et al, 2011; Recanzone, 1998; Wozny et al, 2011). Using the Ventriloquism aftereffect illusion in humans and non-human primates, we recently showed that the coordinate frame in which vision calibrates auditory spatial representation is a mixture between eye-centered and craniocentric, suggesting that perhaps both representations get transformed in a way that is most consistent with the motor commands of the response to stimulation in either modality (Kopco et al, 2009).…”

Early ERP responses to own names while gaming

“…In this range, auditory stimuli typically elicit ERPs identified as the PI, Nl, P2, and N2 waves, which are driven by stimulus factors but also often modulated by attentional or emotional factors [5]. Even in the earlier part of this range, responses reflecting auditory short-term plasticity were reported by recent ERP or magnetoencephalography (MEG) studies [6,7]. Of particular relevance here is the finding that even the P50 MEG responses (MEG analogues of the P50 or the PI) to initially emotionally-neutral clicks were changed after a short learning phase where these clicks were associated with emotionally significant sounds [7].…”