title: Modulation of alpha activity in the parieto-occipital area by distractors during a visuospatial working memory task: a magnetoencephalographic study.
abstract: Oscillatory brain activity is known to play an essential role in information processing in working memory. Recent studies have indicated that alpha activity (8-13 Hz) in the parieto-occipital area is strongly modulated in working memory tasks. However, the function of alpha activity in working memory is open to several interpretations, such that alpha activity may be a direct neural correlate of information processing in working memory or may reflect disengagement from information processing in other brain areas. To examine the functional contribution of alpha activity to visuospatial working memory, we introduced visuospatial distractors during a delay period and examined neural activity from the whole brain using magnetoencephalography. The strength of event-related alpha activity was estimated using the temporal spectral evolution (TSE) method. The results were as follows: (1) an increase of alpha activity during the delay period as indicated by elevated TSE curves was observed in parieto-occipital sensors in both the working memory task and a control task that did not require working memory; and (2) an increase of alpha activity during the delay period was not observed when distractors were presented, although TSE curves were constructed only from correct trials. These results indicate that the increase of alpha activity is not directly related to information processing in working memory but rather reflects the disengagement of attention from the visuospatial input.
authors.affiliation: Sapporo Medical University, Japan.
authors.forename: Satoe
authors.initials: S
authors.lastname: Ichihara-Takeda
authors.forename: Shogo
authors.initials: S
authors.lastname: Yazawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Murahara
authors.forename: Takanobu
authors.initials: T
authors.lastname: Toyoshima
authors.forename: Jun
authors.initials: J
authors.lastname: Shinozaki
authors.forename: Masanori
authors.initials: M
authors.lastname: Ishiguro
authors.forename: Hideaki
authors.initials: H
authors.lastname: Shiraishi
authors.forename: Nozomu
authors.initials: N
authors.lastname: Ikeda
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Matsuyama
authors.forename: Shintaro
authors.initials: S
authors.lastname: Funahashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagamine
mesh_terms: D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009778:Occipital Lobe / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D055815:Young Adult