Contributions of local speech encoding and functional connectivity to audio-visual speech perception
Abstract
Seeing a speaker’s face enhances speech intelligibility in adverse environments. We investigated the underlying network mechanisms by quantifying local speech representations and directed connectivity in MEG data obtained while human participants listened to speech of varying acoustic SNR and visual context. During high acoustic SNR speech encoding by temporally entrained brain activity was strong in temporal and inferior frontal cortex, while during low SNR strong entrainment emerged in premotor and superior frontal cortex. These changes in local encoding were accompanied by changes in directed connectivity along the ventral stream and the auditory-premotor axis. Importantly, the behavioral benefit arising from seeing the speaker’s face was not predicted by changes in local encoding but rather by enhanced functional connectivity between temporal and inferior frontal cortex. Our results demonstrate a role of auditory-frontal interactions in visual speech representations and suggest that functional connectivity along the ventral pathway facilitates speech comprehension in multisensory environments.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 07, 2017
- Source ID
- 10.7554/elife.24763
Entities
People
- Bruno L. Giordano
- Christoph Kayser
- Joachim Gross
- Philippe G Schyns
- Robin A A Ince
- Stefano Panzeri
Organizations
- Aix-Marseille University
- Biotechnology and Biological Sciences Research Council
- Engineering and Physical Sciences Research Council
- European Research Council
- Istituto Italiano di Tecnologia
- United States Department of Defense
- University of Glasgow
- Wellcome Trust