Neural development of networks for audiovisual speech comprehension.
Everyday conversation is both an auditory and a visual phenomenon. While visual speech information enhances comprehension for the listener, evidence suggests that the ability to benefit from this information improves with development. A number of brain regions have been implicated in audiovisual speech comprehension, but the extent to which the neurobiological substrate in the child compares to the adult is unknown. In particular, developmental differences in the network for audiovisual speech comprehension could manifest through the incorporation of additional brain regions, or through different patterns of effective connectivity. In the present study we used functional magnetic resonance imaging and structural equation modeling (SEM) to characterize the developmental changes in network interactions for audiovisual speech comprehension. The brain response was recorded while children 8- to 11-years-old and adults passively listened to stories under audiovisual (AV) and auditory-only (A) conditions. Results showed that in children and adults, AV comprehension activated the same fronto-temporo-parietal network of regions known for their contribution to speech production and perception. However, the SEM network analysis revealed age-related differences in the functional interactions among these regions. In particular, the influence of the posterior inferior frontal gyrus/ventral premotor cortex on supramarginal gyrus differed across age groups during AV, but not A speech. This functional pathway might be important for relating motor and sensory information used by the listener to identify speech sounds. Further, its development might reflect changes in the mechanisms that relate visual speech information to articulatory speech representations through experience producing and perceiving speech.
Department of Neurology, The University of Chicago, IL, USA. adick@uchicago.edu
Anthony Steven
AS
Dick
Ana
A
Solodkin
Steven L
SL
Small
D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D001306:Auditory Pathways / Q000254:growth & development* / Q000502:physiology; D002540:Cerebral Cortex / Q000254:growth & development* / Q000502:physiology; D002648:Child; D032882:Comprehension / Q000502:physiology; D005260:Female; D006801:Humans; D007804:Language Development; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D010775:Photic Stimulation; D013067:Speech Perception / Q000502:physiology*; D014795:Visual Pathways / Q000254:growth & development* / Q000502:physiology; D055815:Young Adult