Distinct prefrontal networks for semantic integration and articulatory planning
Leyao Yu, Nikolai Chapochnikov, Adeen Flinker, New York University, United States
Posters 1 Poster
Pacific Ballroom H-O
Thu, 25 Aug, 19:30 - 21:30 Pacific Time (UTC -7)
The spatiotemporal neural dynamics in frontal cortex underlying speech production remain poorly understood. Growing evidence has implicated the posterior MFG as critical for language alongside inferior frontal gyrus (IFG). We leveraged a battery of language production tasks within a cohort of 24 neurosurgical patients undergoing electrocorticographic monitoring. Focusing on high gamma broadband (70-150 Hz), we employed an unsupervised clustering approach to reveal two new networks in frontal cortex with differentiated articulatory and semantic specificity. The articulatory cluster, centered in IFG and precentral cortices, showed comparable activity prior to speech onset across all tasks. The semantic cluster, centered on the border of IFG and MFG, showed strong task-selectivity prior to articulation with significantly greater activity for tasks requiring semantic access. Neural covariance across time-locked to perception in the semantic cluster highly correlated with the semantic embeddings of the changing auditory stimuli. Our results suggest two distinct language production components distributed across frontal cortices, a preparatory motor-related component agnostic to task, and a component recruited specifically as semantic integration is required.