Modulation of brain connectivity as a function of orthographic interference

Abstract

INTRODUCTION: Research in language and cognitive processing using various neuroimaging methods has definitively demonstrated that these processes involve networks of brain regions (e.g. Friston, 2011; Sauseng et al., 2009). More interesting is the question of how the interaction among brain regions in a network is modulated as a function of changes in some aspect of the underlying processes. This study examined the connectivity among three regions-of-interest in the left hemisphere – posterior fusiform gyrus, posterior temporal cortices, and BA44 known to be associated with visual word form processing, semantic processing, and verbal working memory or executive control, respectively – using brain oscillatory activities with EEG. Changes in phase synchronization in theta (4-7 Hz) and gamma (30-45Hz) frequency bands among ROIs were computed in a picture-word interference paradigm where the target and distractor differed in degree of orthographic similarity. Theta and gamma oscillations are focused on as they are sensitive to linguistic manipulations (Bastiaansen, 2002; 2005) and reflect top-down contro…