Visual, auditory and tactile stimuli compete for early sensory processing capacities within but not between senses

Citation

Porcu E, Keitel C & Müller MM (2014) Visual, auditory and tactile stimuli compete for early sensory processing capacities within but not between senses. NeuroImage, 97, pp. 224-235. https://doi.org/10.1016/j.neuroimage.2014.04.024

Abstract
We investigated whether unattended visual, auditory and tactile stimuli compete for capacity-limited early sensory processing across senses. In three experiments, we probed competitive audio-visual, visuo-tactile and audio-tactile stimulus interactions. To this end, continuous visual, auditory and tactile stimulus streams (‘reference’ stimuli) were frequency-tagged to elicit steady-state responses (SSRs). These electrophysiological oscillatory brain responses indexed ongoing stimulus processing in corresponding senses. To induce competition, we introduced transient frequency-tagged stimuli in same and/or different senses (‘competitors’) during reference presentation. Participants performed a separate visual discrimination task at central fixation to control for attentional biases of sensory processing. A comparison of reference-driven SSR amplitudes between competitor-present and competitor-absent periods revealed reduced amplitudes when a competitor was presented in the same sensory modality as the reference. Reduced amplitudes indicated the competitor's suppressive influence on reference stimulus processing. Crucially, no such suppression was found when a competitor was presented in a different than the reference modality. These results strongly suggest that early sensory competition is exclusively modality-specific and does not extend across senses. We discuss consequences of these findings for modeling the neural mechanisms underlying intermodal attention.

Keywords
EEG; Cross-modal; Inter-modal attention; Biased competition; Multisensory; Steady-state evoked potential

Journal
NeuroImage: Volume 97