A. Wutz: The brain-body dynamics underlying conscious perception across the senses

Abstract
Is our conscious perception of seeing a flash, hearing a sound or feeling a touch associated with one common core brain activity pattern or a specific brain-body interactive state? In this talk, I present novel magneto-encephalography (MEG), cardiac and respiratory data that investigate such supra-sensory neural correlates of conscious perception and its relationships to ongoing dynamics in the body. On each trial, different visual, auditory or tactile stimuli were shown at individual perceptual thresholds, such that about half of the stimuli were consciously detected, while the other half were missed. Four different stimuli per sense were used (i.e. different Gabor patches, sound-frequencies, stimulated fingers), in order to subsequently leverage representational similarity analysis (RSA) for differentiating sensory-specific from supra-sensory processes, which are similar across the sensory modalities. The RSA was capable of distinguishing sensory-related from supra-sensory brain activity patterns. Whereas sensory-specific processes were observed early after stimulus onset (<0.5 s) in the respective sensory cortices, supra-sensory conscious processes occurred later (>0.5 s) in sensory association areas. These findings will be further confirmed by combining MEG and magnetic resonance imaging (MRI) data by means of RSA, in order to establish a comprehensive spatial-temporal picture of supra-sensory conscious perception in the brain. Moreover before stimulus onset, neural activity bursts in the alpha-frequency band (8-13 HZ) were predictive of subsequent conscious perception across the senses. The precise timing of these neural activity bursts was influenced by the participants’ ongoing cardiac and respiratory cycles. Overall, our work aims for an interactive, multi-stage model for conscious multisensory experiences, involving pre-stimulus alpha oscillations, sensory-specific processing upon stimulus onset and then later supra-sensory conscious perception. This temporal processing cascade in the brain may be further modulated by ongoing state changes in the body, in order to serve the optimally timed integration of conscious experiences with the perceiver.

Acknowledgements: This research was supported by project funding from the FWF - the Austrian Science Fund. Grant agreement number: P36214

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