Poster D30, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
Modulation of functional connections from temporal cortex during second language word recognition in noise: does L2 - L1 phonological similarity matter?
Sara Guediche1, Angela de Bruin1, César Caballero-Gaudes1, Martijn Baart1,2, Arthur G. Samuel1,3,4;1Basque Center on Cognition, Brain and Language (BCBL), 2Tilburg University, 3Stony Brook University, 4Ikerbasque Basque Foundation For Science
Spoken word recognition can be hindered by noisy listening conditions, especially when listening in a second language. The current study aims to elucidate the functional networks and modulations in connectivity that support accurate word recognition of a second language, under adverse listening conditions. In particular, we investigate two factors which are known to affect word recognition, namely 1) the phonological similarity of a target word to the native language translation equivalent, and 2) the semantic relationship of a preceding prime word. To this end, a fast-event related fMRI design (using a multi-echo sequence) was conducted. Highly proficient bilingual participants (Spanish-Basque, L1-L2) heard Prime-Target pairs in their second language (Basque) and performed a lexical decision task on the Targets. Word targets varied in the degree of phonological-lexical overlap (cognate type) with the native language (identical cognate, partial cognates, or non-cognates). The preceding prime words were either semantically related or unrelated (semantic priming) to the word targets. We examine whether L2 phonological similarity to L1 affects the integration of information across acoustic and semantic levels of processing and whether the interaction between the two factors involves areas implicated in executive/language control. Not surprisingly, semantic priming improved performance. In contrast, having an L1 cognate impaired performance (replicating a prior behavioral study). For the fMRI analysis, correct and incorrect responses were modeled separately in the GLM model. A whole-brain voxelwise ANOVA analysis (N= 23) on correct responses with Semantic Priming (Related, Unrelated) x Cognate Type as factors showed a significant interaction between semantic relatedness and cognate type in a network consisting of temporal, parietal, and frontal areas. Previous studies in monolingual listeners have shown that connections between frontal and temporal cortical areas are modulated by a predictive context (e.g., Obleser et al., 2007; Gow, 2015; Sohoglu and Davis, 2016). Much of this research has focused on the influence of frontal areas on activity in temporal areas. Here, we conduct a context-dependent functional connectivity analysis (generalized psycho-physiological interactions (gPPI)) using a voxel from the posterior superior temporal gyrus (pSTG) as a seed in order to determine how the relatedness of the prime and the cognate type modulate its functional connections during accurate word recognition (correct responses). We predict that semantic relatedness modulates the functional connections between pSTG and more anterior and inferior temporal areas associated with lexical and semantic processing. Multi-echo fMRI has been shown to prevent signal loss in regions susceptible to signal dropout, thus we expect to better capture potential changes in functional connections to these regions. We also predicted that native language co-activation induced by Cognate Status may modulate cognitive demands, and thus connections to frontal areas, especially when the preceding semantic context is unrelated. Preliminary results from the gPPI analysis seem consistent with these predictions. Specifically, they suggest that, in noisy listening conditions, cognate status affects the need for cognitive control to coordinate lexical knowledge with the acoustic speech signal.
Themes: Meaning: Lexical Semantics, Speech Perception
Method: Functional Imaging