title: Assessing crossmodal matching of abstract auditory and visual stimuli in posterior superior temporal sulcus with MEG.
abstract: Associating crossmodal auditory and visual stimuli is an important component of perception, with the posterior superior temporal sulcus (pSTS) hypothesized to support this. However, recent evidence has argued that the pSTS serves to associate two stimuli irrespective of modality. To examine the contribution of pSTS to crossmodal recognition, participants (N=13) learned 12 abstract, non-linguistic pairs of stimuli over 3weeks. These paired associates comprised four types: auditory-visual (AV), auditory-auditory (AA), visual-auditory (VA), and visual-visual (VV). At week four, participants were scanned using magnetoencephalography (MEG) while performing a correct/incorrect judgment on pairs of items. Using an implementation of synthetic aperture magnetometry that computes real statistics across trials (SAMspm), we directly contrasted crossmodal (AV and VA) with unimodal (AA and VV) pairs from stimulus-onset to 2s in theta (4-8Hz), alpha (9-15Hz), beta (16-30Hz), and gamma (31-50Hz) frequencies. We found pSTS showed greater desynchronization in the beta frequency for crossmodal compared with unimodal trials, suggesting greater activity during the crossmodal pairs, which was not influenced by congruency of the paired stimuli. Using a sliding window SAM analysis, we found the timing of this difference began in a window from 250 to 750ms after stimulus-onset. Further, when we directly contrasted all sub-types of paired associates from stimulus-onset to 2s, we found that pSTS seemed to respond to dynamic, auditory stimuli, rather than crossmodal stimuli per se. These findings support an early role for pSTS in the processing of dynamic, auditory stimuli, and do not support claims that pSTS is responsible for associating two stimuli irrespective of their modality.
authors.affiliation: Brain Imaging and Modeling Section, National Institute on Deafness and Other Communication Disorders, Bethesda, MD 20892, United States. jessica.gilbert@nih.gov
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Gilbert
authors.forename: Ajay S
authors.initials: AS
authors.lastname: Pillai
authors.forename: Barry
authors.initials: B
authors.lastname: Horwitz
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*