Poster I22

Functional Magnetic Resonance Imaging of Syntactic and Prosodic Complexity Effects

Asaf Bachrach¹, Elodie Cauvet¹, Christophe Pallier¹;¹INSERM-CEA Cognitive Neuroimaging Unit, Neurospin, France

Many fMRI studies of sentence processing have manipulated syntactic complexity, attempting to identify neural networks involved in syntactic computations. However, most of them have made use of materials that confounded structural complexity per-se with other factors such as working memory (Stromswold et al 1996), verbal valance (Shetreet et al 2009) or prosodic structure. The present study manipulated syntactic and prosodic complexity in a crossed design, minimizing other differences. The stimuli were 4-member coordinated phrases (e.g. “The goat or the dog and the pig or the chicken”). Three types of syntactic structures were compared: fully right branching, complex middle branch, and complex left branch trees. Prosodic complexity was manipulated by varying the number of prosodic embeddings (3 vs. 2). Subjects performed a truth-verification task against a display presented at phrases' onsets. We found syntactic complexity effects in the Precuneus : both left branching structures activated it more than the right branching structure. 3 levels of prosodic embeddings produced increased activation relative to 2 levels of embeddings in the bilateral anterior Insula as well as the right inferior frontal gyrus. That the Precuneus plays a role in sentence processing has been pointed out by a number of recent studies (Ferstl et al 2008). Our results provide finer characterization of its function, demonstrating that its role is not tied (only) to lexical representation of certain verbs (Shetreet and colleagues) but is implicated in the representation of the abstract syntactic structure itself. Our results suggest a role for the Insula in prosodic structure processing.

Keywords: Primary = LANGUAGE: Syntax; Secondary = METHODS: Neuroimaging

 
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