title: Chronometry of word and picture identification: common and modality-specific effects.
abstract: Based on a previous fMRI connectivity analysis, we previously proposed that long-distance connections between left inferior frontal sulcus and left occipitotemporal sulcus mediate access to visual short-term memory both for written words and pictures enhancing conscious perception and successful encoding in an amodal manner. Using a 64-channel event-related potential electrode system in 19 young cognitively intact volunteers, we determined the chronometry of common and input-modality specific effects of word and picture identification and subsequent memory retrieval. Stimulus durations were calibrated per subject, modality and run so as to reach a 50% positive identification report. The earliest main effect of a positive identification report occurred between 180 and 200 ms, was common for both input-modalities, had a positive polarity and was located at around CPz. This effect was followed between 270 and 450 ms by additional common positive-polarity effects at centrofrontal electrode sites and by common negative effects at P7/P8, TP7/TP8 and T8. Each of the later effects was closely associated not only with identification but also with subsequent memory retrieval. The earliest input-modality specific effect of conscious identification that we detected occurred from 280 till 440 ms at P8. Our findings are in line with a model where the initial stages of perceptual identification and visual short-term memory access rely on long-distance connections that are shared between written words and pictures.
authors.affiliation: Laboratory for Cognitive Neurology, Katholieke Universiteit Leuven, Belgium.
authors.forename: Leen
authors.initials: L
authors.lastname: Van Doren
authors.forename: Maarten
authors.initials: M
authors.lastname: Schrooten
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Adamczuk
authors.forename: Patrick
authors.initials: P
authors.lastname: Dupont
authors.forename: Rik
authors.initials: R
authors.lastname: Vandenberghe
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D012660:Semantics; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult