title: Induced oscillatory responses during the Sternberg's visual memory task in patients with Alzheimer's disease and mild cognitive impairment.
abstract: In this study we used magnetoencephalography during a modified version of the Sternberg's memory recognition task performed by patients with early Alzheimer's disease (AD), mild cognitive impairment (MCI), and by age-matched healthy controls to identify differences in induced oscillatory responses. For analyses, we focused on the retention period of the working memory task. Multiple-source beamformer and Brain Voyager were used for localization of source-power changes across the cortex and for statistic group analyses, respectively. We found significant differences in oscillatory response during the task, specifically in beta and gamma frequency bands: patients with AD showed reduced beta event-related desynchronization (ERD) in the right central area compared to controls, and reduced gamma ERD in the left prefrontal and medial parietal cortex compared to patients with MCI. Our findings suggest that reduced oscillatory responses over certain brain regions in high frequency bands (i.e., beta, gamma), and especially in the beta band that was significantly different between AD patients and healthy subjects, may represent brain electromagnetic changes underlying visual-object working memory dysfunction in early AD, and a neurophysiological indicator of cognitive decline.
authors: Department of Psychiatry, Osaka University Graduate School of Medicine, 2-2 D3, Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Ryu
authors: R
authors: Kurimoto
authors: Ryouhei
authors: R
authors: Ishii
authors: Leonides
authors: L
authors: Canuet
authors: Koji
authors: K
authors: Ikezawa
authors: Masao
authors: M
authors: Iwase
authors: Michiyo
authors: M
authors: Azechi
authors: Yasunori
authors: Y
authors: Aoki
authors: Shunichiro
authors: S
authors: Ikeda
authors: Tetsuhiko
authors: T
authors: Yoshida
authors: Hidetoshi
authors: H
authors: Takahashi
authors: Takayuki
authors: T
authors: Nakahachi
authors: Hiroaki
authors: H
authors: Kazui
authors: Masatoshi
authors: M
authors: Takeda
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D003072:Cognition Disorders / Q000503:physiopathology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*