Visualization of functional and effective connectivity underlying auditory descriptive naming.

OBJECTIVE

We visualized functional and effective connectivity within specific white matter networks in response to auditory descriptive questions.

METHODS

We investigated 40 Japanese-speaking patients with focal epilepsy and estimated connectivity measures using cortical high-gamma dynamics and MRI tractography.

RESULTS

Hearing a wh-interrogative at question onset enhanced inter-hemispheric functional connectivity, with left-to-right callosal facilitatory flows between the superior-temporal gyri, contrasted by functional connectivity diminution with right-to-left callosal suppressive flows between dorsolateral prefrontal regions. Processing verbs associated with concrete objects or adverbs increased left intra-hemispheric connectivity, with bidirectional facilitatory flows through extensive white matter pathways. Questions beginning with what, compared to where, induced greater neural engagement in the left posterior inferior-frontal gyrus at question offset, linked to enhanced functional connectivity and bidirectional facilitatory flows to the temporal lobe neocortex via the arcuate fasciculus. During overt responses, inter-hemispheric functional connectivity was enhanced, with bidirectional callosal flows between Rolandic areas, and individuals with higher IQ scores exhibited less prolonged neural engagement in the left posterior middle frontal gyrus.

CONCLUSIONS

Visualization of directional neural interactions within white matter networks during overt naming is feasible.

SIGNIFICANCE: Phrase order may influence network dynamics in listeners, even when presented with auditory descriptive questions conveying similar meanings.