Is audiotactile temporal recalibration stimulus-specific?

Ignacio Velasco Marugán, Jordi Navarra
Poster
Time: 2009-07-01  09:00 AM – 10:30 AM
Last modified: 2009-06-04

Abstract


Previous studies have shown that the perceptual system is able to adapt to small temporal asynchronies between signals arriving from different sensory modalities (e.g., touch and audition). However, it still remains unclear whether this adaptation is guided by a general mechanism (affecting not only the processing of the asynchronous stimuli, but also the processing of other sounds), or stimulus-specific (e.g., being restricted to the perception of sounds with a specific pitch). Participants received a 3-min exposure to brief 1500-Hz beeps and taps that could be presented either in synchrony or in asynchrony (with a constant lag of 75ms between them). After this exposure phase, the participants performed temporal order judgements (TOJs) regarding a sound and a tap presented at various stimulus onset asynchronies (SOAs). Critically, the sound could be the same (1500Hz) as in the exposure phase or a different (750Hz). Although significant shifts in the point of subjective simultaneity (PSS) were observed after the exposure to asynchrony only in the pre-exposed (and adapted) sound, the difference, in terms of PSS shift, between the pre-exposed and the non-exposed sounds was not significant. This pattern of results suggests the existence of a general (i.e., not stimulus-specific) adaptation mechanism. However, preliminary results using more distant sounds (that may be also more distantly represented in primary auditory cortex, A1; see Formisano et al., 2003) indicate the presence of pitch-specific adaptation effects. Different hypotheses regarding the level of signal processing (e.g., early vs. late) at which temporal recalibration may occur are discussed in the light of these (and previous) results.

Conference System by Open Conference Systems & MohSho Interactive Multimedia