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Front. Integr. Neurosci. | doi: 10.3389/fnint.2019.00067

Optimized Configuration of Functional Brain Network for Processing Semantic Audiovisual Stimuli Underlying the Modulation of Attention: A Graph-based Study

 Yang Xi1,  Qi Li1*, Mengchao Zhang2, Lin Liu2*, Guangjian Li3, Weihong Lin3 and  Jinglong Wu4
  • 1School of Computer Science and Technology, Changchun University of Science and Technology, China
  • 2Department of Radiology, China-Japan Union Hospital, Jilin University, China
  • 3Department of Neurology, First Hospital of Jilin University, China
  • 4Graduate School of Natural Science and Technology, Okayama University, Japan

Semantic audiovisual stimuli have a facilitatory effect on behavioral performance and influence the integration of multisensory inputs across sensory modalities. Many neuroimaging and electrophysiological studies investigated the neural mechanisms of multisensory semantic processing and reported that attention modulates the response to multisensory semantic inputs. In the present study, we designed an fMRI experiment of semantic discrimination using the unimodal auditory, unimodal visual and bimodal audiovisual stimuli with semantic information. By manipulating the stimuli present on attended and unattended position, we recorded the task-related fMRI data corresponding to the unimodal auditory, unimodal visual and bimodal audiovisual stimuli in attended and unattended conditions. We also recorded the fMRI data in resting state. Then the fMRI method was used together with a graph theoretical analysis to construct the functional brain networks in task-related and resting states and quantitatively characterize the topological network properties. The aim of our present study is to explore the characteristics of functional brain networks that process semantic audiovisual stimuli in attended and unattended conditions, revealing the neural mechanism of multisensory processing and the modulation of attention. The behavioral results showed that the audiovisual stimulus presented simultaneously promoted the performance of semantic discrimination task. And the analyses of network properties showed that compared with the resting-state condition, the functional networks of processing semantic audiovisual stimuli (both in attended and unattended conditions) had greater small-worldness, global efficiency, and lower clustering coefficient, characteristic path length, global efficiency and hierarchy. In addition, the hubs were concentrated in the bilateral temporal lobes, especially in the anterior temporal lobes, which were positively correlated to reaction time. Moreover, attention significantly altered the degree of small-worldness and the distribution of hubs in the functional network for processing semantic audiovisual stimuli. Our findings suggest that the topological structure of the functional brain network for processing semantic audiovisual stimulus is modulated by attention, and has the characteristics of high efficiency and low wiring cost, which maintains an optimized balance between functional segregation and integration for multisensory processing efficiently.

Keywords: semantics, Audiovisual stimulus, functional magnetic resonance imaging, functional connectivity, brain network, graph theory

Received: 03 Jul 2019; Accepted: 05 Nov 2019.

Copyright: © 2019 Xi, Li, Zhang, Liu, Li, Lin and Wu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Prof. Qi Li, School of Computer Science and Technology, Changchun University of Science and Technology, Changchun, 130022, Jilin Province, China, liqi@cust.edu.cn
Prof. Lin Liu, Department of Radiology, China-Japan Union Hospital, Jilin University, Changchun, China, liulin5413@126.com