title: Oscillatory activity in auditory cortex reflects the perceptual level of audio-tactile integration.
abstract: Cross-modal interactions between sensory channels have been shown to depend on both the spatial disparity and the perceptual similarity between the presented stimuli. Here we investigate the behavioral and neural integration of auditory and tactile stimulus pairs at different levels of spatial disparity. Additionally, we modulated the amplitudes of both stimuli in either a coherent or non-coherent manner. We found that both auditory and tactile localization performance was biased towards the stimulus in the respective other modality. This bias linearly increases with stimulus disparity and is more pronounced for coherently modulated stimulus pairs. Analyses of electroencephalographic (EEG) activity at temporal-cortical sources revealed enhanced event-related potentials (ERPs) as well as decreased alpha and beta power during bimodal as compared to unimodal stimulation. However, while the observed ERP differences are similar for all stimulus combinations, the extent of oscillatory desynchronization varies with stimulus disparity. Moreover, when both stimuli were subjectively perceived as originating from the same direction, the reduction in alpha and beta power was significantly stronger. These observations suggest that in the EEG the level of perceptual integration is mainly reflected by changes in ongoing oscillatory activity.
authors.affiliation: Institute of Cognitive Science, University of Osnabrück, Albrechtstraße 28, 49069 Osnabrück, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Plöchl
authors.affiliation: Human Research and Engineering Directorate, Army Research Laboratory, Aberdeen Proving Ground, MD, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Gaston
authors.affiliation: Human Research and Engineering Directorate, Army Research Laboratory, Aberdeen Proving Ground, MD, USA.
authors.forename: Tim
authors.initials: T
authors.lastname: Mermagen
authors.affiliation: Institute of Cognitive Science, University of Osnabrück, Albrechtstraße 28, 49069 Osnabrück, Germany.|Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: König
authors.affiliation: Human Research and Engineering Directorate, Army Research Laboratory, Aberdeen Proving Ground, MD, USA.
authors.forename: W David
authors.initials: WD
authors.lastname: Hairston
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception; D001931:Brain Mapping; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014110:Touch; D055815:Young Adult