Presentation

Nicoletta Biondo^1,2, Maria Ivanova¹, Alexis Pracar¹, Juliana Baldo³, Nina Dronkers^1,4; ¹UC Berkeley, ²BCBL, ³VA Northern California Health Care System, ⁴UC Davis

Whether syntactic comprehension, i.e., the ability to assign a hierarchical structure to a sentence in order to successfully interpret its meaning, relies mostly on frontal regions (Friederici, 2017; Hagoort, 2014), e.g., posterior Inferior Frontal Gyrus (pIFG), or on temporal regions (Matchin & Hickock, 2020; Bornkessel-Schlesewsky & Schlesewsky, 2013), e.g., posterior Middle Temporal Gyrus (pMTG), is still debated. Lesion-symptom mapping (LSM) analyses can actively inform this debate by identifying regions that are critical for specific linguistic operations (Bates et al., 2003; Vaidya et al., 2019; Wilson, 2017). With regard to syntactic processing, Dronkers et al. (2004) originally showed that lesions to the pMTG are crucial for lexical/semantic word-level comprehension, and consequently for general comprehension (of different sentence types). Lesions to frontal regions, particularly BA 47 (not BA 44 and 45) were also found to be relevant for the comprehension of relative clauses. More recently, Matchin et al. (2022) showed that the comprehension of non-canonical (object-extracted object clefts, relative clauses, wh- questions) structures were mainly associated with damage to the pMTG, while damage to the pIFG was not implicated. Thus, the role of temporal and frontal regions in syntactic processing remains to be further ascertained. In the current study, we wish to contribute to this debate by analyzing the performance of 150 individuals with post-stroke aphasia on the CYCLE-R test (Curtiss & Yamada, 1988). Data from 64 participants were already reported in Dronkers et al. (2004), while the remaining data were collected subsequently and never published. The subtests Object Clefting (“It’s the clown that the girl chases”) and Relative Pronouns with Double Function (“The girl who the boy is pushing is happy”) involving reversible sentences with an extracted object NP will be grouped under the non-canonical condition. We will also investigate complex structures with no object extraction (subtests: Subject relatives “The girl who is pushing the boy is happy”, Object relative clauses “The girl is chasing the clown who is big”), which appeared to involve frontal regions in previous analyses. Performance on the Active Voice Word Order subtest (“The girl is pulling the boy”), which includes similar nouns and verbs, will be considered as a covariate in the analyses (as in Matchin et al., 2022). An LSM analysis with both univariate and multivariate methods will be implemented to detect areas associated with the processing of these two types of complex sentences while controlling for comprehension of simple canonical sentences, as well as relevant demographic and lesion variables (Ivanova et al., 2021). Dronkers et al. (2004) reported that lesions in temporal regions (anterior BA 22, Superior Temporal Sulcus (STS) BA 39) affected performance on the Object Clefting subtest. Therefore, these regions are expected to play a bigger role compared to frontal regions, such as the pIFG. Frontal regions (such as BA 46 and 47) may play a role in structures with a different type of syntactic complexity, such as relative clauses with no object extraction. Overall, the current study will be informative for advancing neural models of syntax.

Topic Areas: Syntax, Disorders: Acquired