In the early and mid 1800s, scientists debated whether the human brain was functionally differentiated with respect to cognition. The issue was largely resolved when specific language impairments were identified following focal patterns of brain damage. However, neuroimaging has revived this discussion, as many studies find similar syntactic and semantic effects across the set of brain regions implicated in language. Here we address this modern debate using lesion-symptom mapping in two large, partially-overlapping groups of people with left hemisphere brain damage due to stroke (N=121, N=92). We identified multiple measure by region interaction effects, associating damage to the posterior middle temporal gyrus with syntactic comprehension deficits, damage to posterior inferior frontal gyrus with expressive agrammatism, and damage to inferior angular gyrus with semantic category word fluency deficits. Our results are inconsistent with recent hypotheses that regions of the language network play similar roles in high-level linguistic processing.
bioRxiv Subject Collection: Neuroscience