The Spatiotemporal Dynamics of Syntax in Language Production and Perception – DynSyn

The goal of this project is to study the neurobiology of syntax, the brain’s ability to structure linguistic elements and create meaning, focusing on two understudied topics: (1) Spatiotemporal dynamics, namely ‘how do the neural sources of basic combinatorial syntax manifest over time?’; (2) Language modality, namely ‘do the perception and production of combinatorial syntax rely on the same neural machinery?’. Addressing these two questions is important because the quite disperse neurobiological models of syntax make different predictions with regard to the degree of spatiotemporal and language modality integration. Hence, investigation these two dimensions will provide insights to constrain brain language models from a novel perspective. More concretely, in this project we will focus on two core brain regions routinely associated with syntactic processing, the left posterior temporal lobe (LPTL) and the left inferior frontal gyrus (LIFG), and test (1) whether they form a parallel integrated network or rather serve distinct functions over time; and (2) whether their dynamics are identical or not when perceiving vs producing syntax. To test these predictions, we propose to adapt a novel paradigm, the minimalistic paradigm, where we will contrast the final word of simple three-word noun phrases (NPs) that differ in their syntactic tree and computation (e.g., a left-branching Adjective-NP ‘joli buisson fleuri’ vs. a right-branching Adverb-NP ‘buisson joliment fleuri’). This paradigm will be used in three Work Packages (WPs): In WP1 we will test the spatiotemporal dynamics (high-density EEG) in perception (exp1) and production (exp2) separately. In WP2 we will test (MEG) perception and production within the same brain (exp3). And in WP3 we will test the two interlocutors simultaneously (EEG hyper-scanning) while interacting with each other using the minimal NPs (exp4). In sum, this project will assess the degree of spatiotemporal integration of the syntactic parser across the language modalities, allowing to constrain neurobiological models of syntax in function of linguistic behavior and social interaction.