Revisiting the cortical architecture of language: evidence from left-hemisphere gliomas

Current wisdom of the organization of language in the brain has been shaped primarily by evidence from people with post-stroke aphasia, often emphasizing the role of Broca's and Wernicke's areas for production and comprehension respectively. However, this view may be obscured by the contributions of regions less frequently affected by middle cerebral artery infarcts. To overcome this limitation, we investigated the neural correlates of word- and sentence-level comprehension and production in 115 individuals with left-hemisphere gliomas using multivariate lesion-symptom mapping. Our findings challenge the traditional segregation of language modalities. Both word and sentence tasks were affected by damage to the anterior temporal lobe (ATL), inferior central regions, and inferior frontal gyrus, with additional involvement of the inferior parietal and posterior temporal regions for sentence processing only. Notably, lesions to the ATL impacted both comprehension and production, whereas posterior temporal damage selectively affected sentence-level performance. These findings highlight the importance of considering lesion etiology when investigating the neural architecture of language, suggesting that the classical dichotomy between "production-frontal" and "comprehension-temporal" areas oversimplifies the distributed nature of the language network. Clinically, our findings suggest that intraoperative paradigms relying solely on single-word naming may fail to identify regions critical for sentence-level processing.