title: Working memory coding of analog stimulus properties in the human prefrontal cortex.
abstract: Building on evidence for working memory (WM) coding of vibrotactile frequency information in monkey prefrontal cortex, recent electroencephalography studies found frequency processing in human WM to be reflected by quantitative modulations of prefrontal upper beta activity (20-30 Hz) as a function of the to-be-maintained stimulus attribute. This kind of stimulus-dependent activity has been observed across different sensory modalities, suggesting a generalized role of prefrontal beta during abstract WM processing of quantitative magnitude information. However, until now the available empirical evidence for such quantitative WM representation remains critically limited to the retention of periodic stimulus frequencies. In the present experiment, we used retrospective cueing to examine the quantitative WM processing of stationary (intensity) and temporal (duration) attributes of a previously presented tactile stimulus. We found parametric modulations of prefrontal beta activity during cued WM processing of each type of quantitative information, in a very similar manner as had before been observed only for periodic frequency information. In particular, delayed prefrontal beta modulations systematically reflected the magnitude of the retrospectively selected stimulus attribute and were functionally linked to successful behavioral task performance. Together, these findings converge on a generalized role of stimulus-dependent prefrontal beta-band oscillations during abstract scaling of analog quantity information in human WM.
authors.affiliation: Dahlem Institute for Neuroimaging of Emotion, Freie Universität Berlin, Berlin 14195, Germany, bernhard.spitzer@fu-berlin.de.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Spitzer
authors.affiliation: Bernstein Center for Computational Neuroscience, Berlin 10115, Germany and.
authors.forename: Matthias
authors.initials: M
authors.lastname: Gloel
authors.affiliation: Bernstein Center for Computational Neuroscience, Berlin 10115, Germany and Center for Adaptive Rationality (ARC), Max Planck Institute for Human Development, Berlin 14195, Germany.
authors.forename: Timo T
authors.initials: TT
authors.lastname: Schmidt
authors.affiliation: Dahlem Institute for Neuroimaging of Emotion, Freie Universität Berlin, Berlin 14195, Germany, Center for Adaptive Rationality (ARC), Max Planck Institute for Human Development, Berlin 14195, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Blankenburg
mesh_terms: D000328:Adult; D001611:Beta Rhythm; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D010812:Physical Stimulation; D017397:Prefrontal Cortex / Q000502:physiology*; D011930:Reaction Time; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D055698:Touch Perception / Q000502:physiology*; D014732:Vibration; D055815:Young Adult
keywords: EEG; oscillations; somatosensory; stimulus coding; working memory