title: Time-resolved neuroimaging of visual short term memory consolidation by post-perceptual attention shifts.
abstract: Post-perceptual cues can enhance visual short term memory encoding even after the offset of the visual stimulus. However, both the mechanisms by which the sensory stimulus characteristics are buffered as well as the mechanisms by which post-perceptual selective attention enhances short term memory encoding remain unclear. We analyzed late post-perceptual event-related potentials (ERPs) in visual change detection tasks (100ms stimulus duration) by high-resolution ERP analysis to elucidate these mechanisms. The effects of early and late auditory post-cues (300ms or 850ms after visual stimulus onset) as well as the effects of a visual interference stimulus were examined in 27 healthy right-handed adults. Focusing attention with post-perceptual cues at both latencies significantly improved memory performance, i.e. sensory stimulus characteristics were available for up to 850ms after stimulus presentation. Passive watching of the visual stimuli without auditory cue presentation evoked a slow negative wave (N700) over occipito-temporal visual areas. N700 was strongly reduced by a visual interference stimulus which impeded memory maintenance. In contrast, contralateral delay activity (CDA) still developed in this condition after the application of auditory post-cues and was thereby dissociated from N700. CDA and N700 seem to represent two different processes involved in short term memory encoding. While N700 could reflect visual post processing by automatic attention attraction, CDA may reflect the top-down process of searching selectively for the required information through post-perceptual attention.
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe University Frankfurt, Deutschordenstraße 50, D-60528 Frankfurt/Main, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Hecht
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe University Frankfurt, Deutschordenstraße 50, D-60528 Frankfurt/Main, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Medical Faculty, University of Cologne, Robert-Koch-Str. 10, D-59031 Köln, Germany.
authors.forename: Ulf
authors.initials: U
authors.lastname: Thiemann
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe University Frankfurt, Deutschordenstraße 50, D-60528 Frankfurt/Main, Germany.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Freitag
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe University Frankfurt, Deutschordenstraße 50, D-60528 Frankfurt/Main, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Medical Faculty, University of Cologne, Robert-Koch-Str. 10, D-59031 Köln, Germany; Department of Child and Adolescent Psychiatry, Dresden University of Technology, Fetscherstraße 74, D-01307 Dresden, Germany. Electronic address: Stephan.Bender@uk-koeln.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Bender
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D000069077:Memory Consolidation / Q000502:physiology*; D008570:Memory, Short-Term / Q000502:physiology*; D059906:Neuroimaging / Q000379:methods*
keywords: Auditory post-perceptual cue; Change detection task; Contralateral delay activity; Event-related potentials; Fragile visual short term memory; N700; Retro cue