Network dynamics of Broca’s area during word selection

• DOI: 10.1371/journal.pone.0225756
• Publication Date: 2019-12-20T18:30:09Z
• Authors: Christopher R. Co...; Cihan M. Kadipasa...; Harel Z. Shouval; Gregory Hickok; Nitin Tandon
• Keywords: Adult; Male; Science; Q; R; Vocabulary; Broca Area; 03 medical and health sciences; 0302 clinical medicine; Acoustic Stimulation; Reaction Time; Medicine; Gamma Rhythm; Humans; Speech; Female; Nerve Net; Research Article; Language

AbstractCurrent models of word-production in Broca’s area posit that sequential and staggered semantic, lexical, phonological and articulatory processes precede articulation. Using millisecond-resolution intra-cranial recordings, we evaluated spatiotemporal dynamics and high frequency functional interconnectivity between ventro-lateral prefrontal regions during single-word production. Through the systematic variation of retrieval, selection, and phonological loads, we identified specific activation profiles and functional coupling patterns between these regions that fit within current psycholinguistic theories of word production. However, network interactions underpinning these processes activate in parallel (not sequentially), while the processes themselves are indexed by specific changes in network state. We found evidence that suggests that pars orbitalis is coupled with pars triangularis during lexical retrieval, while lexical selection in Broca’s area is terminated via coupled activity with M1 at articulation onset. Taken together, this work reveals that speech production relies on very specific inter-regional couplings in rapid sequence in the language dominant hemisphere.