title: Lexical memory search during N400: cortical couplings in auditory comprehension.
abstract: In this study, we applied partial-directed EEG-coherence analysis to assess regional changes in neuronal couplings and information transfer related to semantic processing. We tested the hypothesis whether (and which) processing differences between spoken words and pseudowords are reflected by changes in cortical networks within the time window of a specific event related potential (ERP) component, the N400. Fourteen native speaking German subjects performed a lexical decision paradigm, while being confronted sequentially with two-syllabic nouns and phonologically legal pseudowords. Using ERP analysis, we defined the time window of the N400 effect, known to reflect semantic processing, and, subsequently, we examined the coupling differences. Lexico-semantic memory search appears to be subserved by a network between temporal, parietal and frontal areas, particularly restricted to the left hemisphere.
authors.affiliation: Institute of Human-Computer Interfaces, University of Technology, Inffeldgasse 16a, A-8010 Graz, Austria. supp@tugraz.at
authors.forename: Gernot G
authors.initials: GG
authors.lastname: Supp
authors.forename: Alois
authors.initials: A
authors.lastname: Schlögl
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Gunter
authors.forename: Montaine
authors.initials: M
authors.lastname: Bernard
authors.forename: Gert
authors.initials: G
authors.lastname: Pfurtscheller
authors.forename: Hellmuth
authors.initials: H
authors.lastname: Petsche
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D000704:Analysis of Variance; D001307:Auditory Perception / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008568:Memory / Q000502:physiology*