Poster D31, Friday, August 17, 4:45 – 6:30 pm, Room 2000AB

Left dorsal white-matter microstructure and oscillatory coupling jointly predict language comprehension

Benedict Vassileiou1, Caroline Beese1, Angela D. Friederici1, Lars Meyer1;1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

Language comprehension emerges from electrophysiological information transfer between neuroanatomically connected brain areas. We thus hypothesized that language comprehension can be jointly predicted from the integrity of white-matter connections and the electrophysiological coupling between their termination regions. We recorded the scalp electroencephalogram of 20 participants who performed a language-encoding task; in addition, we acquired diffusion-weighted magnetic resonance images. Electrophysiological coupling was quantified in source space employing the debiased weighted phase-lag index (dwPLI). Following our prior work, we calculated dwPLI in the alpha band between frontal and posterior nodes of the left perisylvian language network. The anatomical integrity of the underlying dorsal and ventral white-matter structures was quantified by calculating their fractional anisotropy (FA). We then fitted statistical models to predict comprehension accuracy from dwPLI, dorsal FA, ventral FA, and their interactions. Our results showed that comprehension accuracy was near-perfectly fitted by an interaction between dwPLI and the FA of the left dorsal white matter: High axonal integrity, in concert with high functional desynchronization, predicted high accuracy. In the framework of alpha-band oscillations as a cortical mechanism of inhibition/disinhibition, our findings suggest that a disinhibitory functional desynchronization of the left dorsal perisylvian language network, supported by its microstructural profile, helps language comprehension. Our result is novel evidence that language comprehension is the outcome of complex relationships between rigid neuroanatomical connections and dynamic electrophysiological crosstalk.

Topic Area: Grammar: Syntax