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Kumar, Vinodh G and Dutta, Shrey and Talwar, Siddharth and Roy, Dipanjan and Banerjee, Arpan (2018) Neurodynamic Explanation of Inter-Individual and Inter-Trial Variability in Cross-Modal Perception. bioRxiv. (In Press)

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A widely used experimental design in multisensory integration is the McGurk paradigm that 12 entail illusory (cross-modal) perception of speech sounds when presented with incongruent 13 audio-visual (AV) stimuli. However, the distribution of responses across trials and 14 individuals is heterogeneous and not necessarily everyone in a given group of individuals 15 perceives the effect. Nonetheless, existing studies in the field primarily focus on addressing 16 the correlation between subjective behavior and cortical activations to reveal the neuronal 17 mechanisms underlying the perception of McGurk effect, typically in the “frequent 18 perceivers”. Additionally, a solely neuroimaging approach does not provide mechanistic 19 explanation for the observed inter-trial or inter-individual heterogeneity. In the current study 20 we employ high density electroencephalogram (EEG) recordings in a group of 25 human 21 subjects that allow us to distinguish “frequent perceivers” from “rare perceivers” using 22 behavioral responses as well as from the perspective of large-scale brain functional 23 connectivity (FC). Using global coherence as a measure of large-scale FC, we find that alpha 24 band coherence, a distinctive feature in frequent perceivers is absent in the rare perceivers. 25 Secondly, a decrease in alpha band coherence and increase in gamma band coherence occur 26 during illusory perception trials in both frequent and rare perceivers. Source analysis 27 followed up with source time series reconstructions reveals a large scale network of brain 28 areas involving frontal, temporal and parietal areas that are involved in network level 29 processing of cross-modal perception. Finally, we demonstrate that how a biophysically 30 realistic computational model representing the interaction among key neuronal systems 31 (visual, auditory and multisensory cortical regions) can explain the empirical observations. 32 Each system involves a group of excitatory and inhibitory Hindmarsh Rose neurons that are 33 coupled amongst each other. Large-scale FC between areas is conceptualized using coupling 34 functions and the identity of a specific system, e.g., visual/ auditory/ multisensory is chosen 35 using empirical estimates of the time-scale of information processing in these systems. The 36 model predicts that the disappearance of alpha band coherence observed in rare perceivers 37 stems from a negligible direct A-V (audio-visual) coupling however, an increase in indirect 38 interaction via multisensory node leads to enhanced gamma band and reduced alpha band 39 coherences observed during illusory perception. Overall, we establish the mechanistic basis 40 of large-scale FC patterns underlying cross-modal perception.

Item Type: Article
Subjects: Neurodegenerative Disorders
Neuro-Oncological Disorders
Neurocognitive Processes
Neuronal Development and Regeneration
Informatics and Imaging
Genetics and Molecular Biology
Depositing User: Dr. D.D. Lal
Date Deposited: 05 Nov 2019 06:38
Last Modified: 18 Feb 2022 04:07
URI: http://nbrc.sciencecentral.in/id/eprint/526

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