title: Hierarchical functional connectivity between the core language system and the working memory system.
abstract: Language processing inevitably involves working memory (WM) operations, especially for sentences with complex syntactic structures. Evidence has been provided for a neuroanatomical segregation between core syntactic processes and WM, but the dynamic relation between these systems still has to be explored. In the present functional magnetic resonance imaging (fMRI) study, we investigated the network dynamics of regions involved in WM operations which support sentence processing during reading, comparing a set of dynamic causal models (DCM) with different assumptions about the underlying connectional architecture. The DCMs incorporated the core language processing regions (pars opercularis and middle temporal gyrus), WM related regions (inferior frontal sulcus and intraparietal sulcus), and visual word form area (fusiform gyrus). The results indicate a processing hierarchy from the visual to WM to core language systems, and moreover, a clear increase of connectivity between WM regions and language regions as the processing load increases for syntactically complex sentences.
authors.affiliation: Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors.forename: Michiru
authors.initials: M
authors.lastname: Makuuchi
authors.forename: Angela D
authors.initials: AD
authors.lastname: Friederici
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D011932:Reading; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: Complex syntax; Dynamic causal modeling; Language network; Working memory; fMRI