Cortical sites critical to language function act as connectors between language subnetworks

• Published in: Nature communications Vol. 15; no. 1; pp. 7897 - 13
• Main Authors: Hsieh, Jason K., Prakash, Prashanth R., Flint, Robert D., Fitzgerald, Zachary, Mugler, Emily, Wang, Yujing, Crone, Nathan E., Templer, Jessica W., Rosenow, Joshua M., Tate, Matthew C., Betzel, Richard, Slutzky, Marc W.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16.09.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 631/378/116/1925; 631/378/2649/1594; 9/26; Adult; Brain; Brain Mapping; Cerebral cortex; Cerebral Cortex - physiology; Computer networks; Connectors; Electrocorticography; Errors; Female; Humanities and Social Sciences; Humans; Language; Machine Learning; Male; Modules; multidisciplinary; Nerve Net - physiology; Neural networks; Science; Science (multidisciplinary); Speech; Speech - physiology; Stimulation; Young Adult
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-51839-z

Historically, eloquent functions have been viewed as localized to focal areas of human cerebral cortex, while more recent studies suggest they are encoded by distributed networks. We examined the network properties of cortical sites defined by stimulation to be critical for speech and language, using electrocorticography from sixteen participants during word-reading. We discovered distinct network signatures for sites where stimulation caused speech arrest and language errors. Both demonstrated lower local and global connectivity, whereas sites causing language errors exhibited higher inter-community connectivity, identifying them as connectors between modules in the language network. We used machine learning to classify these site types with reasonably high accuracy, even across participants, suggesting that a site’s pattern of connections within the task-activated language network helps determine its importance to function. These findings help to bridge the gap in our understanding of how focal cortical stimulation interacts with complex brain networks to elicit language deficits. It is unknown how cortical stimulation identifies brain regions critical to speech and language when they depend upon broader brain networks. Here the authors show that these critical areas function as connectors between modules in the language network.