title: Integration demands modulate effective connectivity in a fronto-temporal network for contextual sentence integration.
abstract: Previous neuroimaging studies demonstrated that a network of left-hemispheric frontal and temporal brain regions contributes to the integration of contextual information into a sentence. However, it remains unclear how these cortical areas influence and drive each other during contextual integration. The present study used dynamic causal modeling (DCM) to investigate task-related changes in the effective connectivity within this network. We found increased neural activity in left anterior inferior frontal gyrus (aIFG), posterior superior temporal sulcus/middle temporal gyrus (pSTS/MTG) and anterior superior temporal sulcus/MTG (aSTS/MTG) that probably reflected increased integration demands and restructuring attempts during the processing of unexpected or semantically anomalous relative to expected endings. DCM analyses of this network revealed that unexpected endings increased the inhibitory influence of left aSTS/MTG on pSTS/MTG during contextual integration. In contrast, during the processing of semantically anomalous endings, left aIFG increased its inhibitory drive on pSTS/MTG. Probabilistic fiber tracking showed that effective connectivity between these areas is mediated by distinct ventral and dorsal white matter association tracts. Together, these results suggest that increasing integration demands require an inhibition of the left pSTS/MTG, which presumably reflects the inhibition of the dominant expected sentence ending. These results are important for a better understanding of the neural implementation of sentence comprehension on a large-scale network level and might influence future studies of language in post-stroke aphasia after focal lesions.
authors.affiliation: Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany; Language & Aphasia Laboratory, Department of Neurology, University of Leipzig, Germany. Electronic address: hartwigsen@cbs.mpg.de.
authors.forename: Gesa
authors.initials: G
authors.lastname: Hartwigsen
authors.affiliation: Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Ilona
authors.initials: I
authors.lastname: Henseler
authors.affiliation: Language & Aphasia Laboratory, Department of Neurology, University of Leipzig, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Stockert
authors.affiliation: Language & Aphasia Laboratory, Department of Neurology, University of Leipzig, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Wawrzyniak
authors.affiliation: Language & Aphasia Laboratory, Department of Neurology, University of Leipzig, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Wendt
authors.affiliation: Language & Aphasia Laboratory, Department of Neurology, University of Leipzig, Germany.
authors.forename: Julian
authors.initials: J
authors.lastname: Klingbeil
authors.affiliation: Department of Speech Language Pathology, Hochschule Fresenius Hamburg, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Baumgaertner
authors.affiliation: Language & Aphasia Laboratory, Department of Neurology, University of Leipzig, Germany.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Saur
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D003657:Decision Making / Q000502:physiology; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008962:Models, Theoretical; D009433:Neural Inhibition / Q000502:physiology*; D017397:Prefrontal Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D012660:Semantics; D013067:Speech Perception / Q000502:physiology*; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000502:physiology*; D066127:White Matter / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Dynamic causal modeling; Inferior frontal gyrus; Language; Priming; Semantic processing; Temporal cortex