Two cortical mechanisms support the integration of visual and auditory speech: A hypothesis and preliminary data

NEUROSCIENCE LETTERS

卷:452

Article

Okada, Kayoko¹  Hickok, Gregory¹ 

[1] Univ Calif Irvine, Dept Cognit Sci, Irvine, CA 92697 USA

关键词: Planum temporale;    fMRI;    Sensory-motor integration;    Lip-reading;    Speech-reading;    Visual speech;    Audio-visual speech;   

DOI  :  10.1016/j.neulet.2009.01.060

来源: Elsevier

【 摘 要 】

Visual speech (lip-reading) influences the perception of heard speech. The literature suggests at least two possible mechanisms for this influence: direct sensory-sensory interaction, whereby sensory signals from auditory and visual modalities are integrated directly, likely in the superior temporal sulcus, and indirect sensory-motor interaction, whereby visual speech is first mapped onto motor-speech representations in the frontal lobe, which in turn influences sensory perception via sensory-motor integration networks. We hypothesize that both mechanisms exist, and further that previous demonstrations of lip-reading functional activations in Broca's region and the posterior planum temporale reflect the sensory-motor mechanism. We tested one prediction of this hypothesis using fMRI. We assessed whether viewing visual speech (contrasted with facial gestures) activates the same network as a speech sensory-motor integration task (listen to and then silently rehearse speech). Both tasks activated locations within Broca's area, dorsal premotor cortex, and the posterior planum temporal (Spt), and focal regions of the STS, all of which have previously been implicated in sensory-motor integration for speech. This finding is consistent with the view that visual speech influences heard speech via sensory-motor networks. Lip-reading also activated a much wider network in the superior temporal lobe than the sensory-motor task, possibly reflecting a more direct cross-sensory integration network. (c) 2009 Elsevier Ireland Ltd. All rights reserved.

【 授权许可】

Free