title: Prediction Signatures in the Brain: Semantic Pre-Activation during Language Comprehension.
abstract: There is broad agreement that context-based predictions facilitate lexical-semantic processing. A robust index of semantic prediction during language comprehension is an evoked response, known as the N400, whose amplitude is modulated as a function of semantic context. However, the underlying neural mechanisms that utilize relations of the prior context and the embedded word within it are largely unknown. We measured magnetoencephalography (MEG) data while participants were listening to simple German sentences in which the verbs were either highly predictive for the occurrence of a particular noun (i.e., provided context) or not. The identical set of nouns was presented in both conditions. Hence, differences for the evoked responses of the nouns can only be due to differences in the earlier context. We observed a reduction of the N400 response for highly predicted nouns. Interestingly, the opposite pattern was observed for the preceding verbs: highly predictive (that is more informative) verbs yielded stronger neural magnitude compared to less predictive verbs. A negative correlation between the N400 effect of the verb and that of the noun was found in a distributed brain network, indicating an integral relation between the predictive power of the verb and the processing of the subsequent noun. This network consisted of left hemispheric superior and middle temporal areas and a subcortical area; the parahippocampus. Enhanced activity for highly predictive relative to less predictive verbs, likely reflects establishing semantic features associated with the expected nouns, that is a pre-activation of the expected nouns.
authors.affiliation: MEG and Cortical Networks Group, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Maess
authors.affiliation: MEG and Cortical Networks Group, Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Department of Neurology, Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical SchoolBoston, MA, USA.
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Mamashli
authors.affiliation: Max Planck Research Group "Auditory Cognition", Max Planck Institute for Human Cognitive and Brain SciencesLeipzig, Germany; Department of Psychology, University of LübeckLübeck, Germany.
authors.forename: Jonas
authors.initials: J
authors.lastname: Obleser
authors.affiliation: Elekta OyHelsinki, Finland; Department of Neuroscience and Biomedical Engineering, School of Science, Aalto UniversityEspoo, Finland.
authors.forename: Liisa
authors.initials: L
authors.lastname: Helle
authors.affiliation: Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences Leipzig, Germany.
authors.forename: Angela D
authors.initials: AD
authors.lastname: Friederici
keywords: MEG; N400; language; prediction; semantics