title: Frontal theta is a signature of successful working memory manipulation.
abstract: It has been proposed that working memory (WM) is updated/manipulated via a fronto-basal-ganglia circuit. One way that this could happen is via the synchronization of neural oscillations. A first step toward testing this hypothesis is to clearly establish a frontal scalp EEG signature of WM manipulation. Although many EEG studies have indeed revealed frontal EEG signatures for WM, especially in the theta frequency band (3-8 Hz), few of them required subjects to manipulate WM, and of those that did, none specifically tied the EEG signature to the manipulation process per se. Here we employed a WM manipulation task that has been shown with imaging to engage the prefrontal cortex and the striatum. We adapted this task to titrate the success of WM manipulation to approximately 50 %. Using time-frequency analysis of EEG, we showed that theta power increased over frontal cortex for successful versus failed WM manipulation, specifically at the time of the manipulation event. This establishes a clear-cut EEG signature of WM manipulation. Future studies could employ this to test the fronto-basal-ganglia hypothesis of WM updating/manipulation.
authors.affiliation: Neurosciences Graduate Program, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
authors.forename: Sirawaj
authors.initials: S
authors.lastname: Itthipuripat
authors.forename: Jan R
authors.initials: JR
authors.lastname: Wessel
authors.forename: Adam R
authors.initials: AR
authors.lastname: Aron
mesh_terms: D000293:Adolescent; D000328:Adult; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D012691:Serial Learning / Q000502:physiology; D013826:Theta Rhythm / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult