title: Recurrence of task set-related MEG signal patterns during auditory working memory.
abstract: Processing of auditory spatial and non-spatial information in working memory has been shown to rely on separate cortical systems. While previous studies have demonstrated differences in spatial versus non-spatial processing from the encoding of to-be-remembered stimuli onwards, here we investigated whether such differences would be detectable already prior to presentation of the sample stimulus. We analyzed broad-band magnetoencephalography data from 15 healthy adults during an auditory working memory paradigm starting with a visual cue indicating the task-relevant stimulus feature for a given trial (lateralization or pitch) and a subsequent 1.5-s pre-encoding phase. This was followed by a sample sound (0.2s), the delay phase (0.8s) and a test stimulus (0.2s) after which participants made a match/non-match decision. Linear discriminant functions were trained to decode task-specific signal patterns throughout the task, and temporal generalization was used to assess whether the neural codes discriminating between the tasks during the pre-encoding phase would recur during later task periods. The spatial versus non-spatial tasks could indeed be discriminated after the onset of the cue onwards, and decoders trained during the pre-encoding phase successfully discriminated the tasks during both sample stimulus encoding and during the delay phase. This demonstrates that task-specific neural codes are established already before the memorandum is presented and that the same patterns are reestablished during stimulus encoding and maintenance. This article is part of a Special Issue entitled SI: Auditory working memory.
authors.affiliation: Institute of Medical Psychology, Goethe University, Heinrich-Hoffmann-Str.10, 60528 Frankfurt am Main, Germany. Electronic address: benjamin.peters@posteo.de.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Peters
authors.affiliation: Institute of Medical Psychology, Goethe University, Heinrich-Hoffmann-Str.10, 60528 Frankfurt am Main, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bledowski
authors.affiliation: Institute of Medical Psychology, Goethe University, Heinrich-Hoffmann-Str.10, 60528 Frankfurt am Main, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Rieder
authors.affiliation: Institute of Medical Psychology, Goethe University, Heinrich-Hoffmann-Str.10, 60528 Frankfurt am Main, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Kaiser
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D003463:Cues; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D016014:Linear Models; D015225:Magnetoencephalography; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D012815:Signal Processing, Computer-Assisted; D065852:Spatial Memory / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: Auditory working memory; Decoding; Magnetoencephalography (MEG); Spatial versus non-spatial processing; Temporal generalization