title: Time course of conscious and unconscious semantic brain activation.
abstract: Event-related brain potentials (ERPs) were used to investigate the neurophysiological correlates of conscious and unconscious semantic processing. Masked words, which do not enter consciousness, as well as visible words, were shown to modulate the N400 ERP potential to subsequently presented, meaningfully related target words. The N400 is known as an electrophysiological index of semantic processing. However, for unconsciously perceived words semantic brain activation decays fast within 200 ms, but increases with time for consciously perceived words. Thus, conscious and unconscious semantic activation involves similar brain areas, but both forms of processes exhibit distinct, qualitatively different time courses.
authors.affiliation: University of Ulm, Department of Psychiatry, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kiefer
authors.forename: M
authors.initials: M
authors.lastname: Spitzer
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D003243:Consciousness / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D014473:Unconscious, Psychology; D014705:Verbal Behavior / Q000502:physiology*