title: Impact of language on functional connectivity for audiovisual speech integration.
abstract: Visual information about lip and facial movements plays a role in audiovisual (AV) speech perception. Although this has been widely confirmed, previous behavioural studies have shown interlanguage differences, that is, native Japanese speakers do not integrate auditory and visual speech as closely as native English speakers. To elucidate the neural basis of such interlanguage differences, 22 native English speakers and 24 native Japanese speakers were examined in behavioural or functional Magnetic Resonance Imaging (fMRI) experiments while mono-syllabic speech was presented under AV, auditory-only, or visual-only conditions for speech identification. Behavioural results indicated that the English speakers identified visual speech more quickly than the Japanese speakers, and that the temporal facilitation effect of congruent visual speech was significant in the English speakers but not in the Japanese speakers. Using fMRI data, we examined the functional connectivity among brain regions important for auditory-visual interplay. The results indicated that the English speakers had significantly stronger connectivity between the visual motion area MT and the Heschl's gyrus compared with the Japanese speakers, which may subserve lower-level visual influences on speech perception in English speakers in a multisensory environment. These results suggested that linguistic experience strongly affects neural connectivity involved in AV speech integration.
authors: Department of Systems Neuroscience, School of Medicine, Sapporo Medical University, Sapporo, Japan.
authors: Jun
authors: J
authors: Shinozaki
authors: ATR Neural Information Analysis Laboratories, Seika-cho, Japan.
authors: Nobuo
authors: N
authors: Hiroe
authors: ATR Neural Information Analysis Laboratories, Seika-cho, Japan.
authors: Masa-Aki
authors: MA
authors: Sato
authors: Department of Systems Neuroscience, School of Medicine, Sapporo Medical University, Sapporo, Japan.
authors: Takashi
authors: T
authors: Nagamine
authors: Division of Cognitive Psychology, Faculty of Letters, Kumamoto University, Kumamoto, Japan.
authors: Kaoru
authors: K
authors: Sekiyama
mesh_terms: D000161:Acoustic Stimulation; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010775:Photic Stimulation; D013067:Speech Perception / Q000502:physiology*; D014796:Visual Perception; D055815:Young Adult