ヤマナカ ケンタロウ    YAMANAKA Kentarou
   山中 健太郎
   所属
生活科学部 健康デザイン学科
 
生活機構研究科 生活科学研究専攻
 
生活機構研究科 生活機構学専攻
 
女性健康科学研究所 所属教員
   職種
教授
言語種別 英語
発行・発表の年月 2014/05
形態種別 学術雑誌
査読 査読あり
標題 Revealing time-unlocked brain activity from MEG measurements by Common Waveform Estimation.
執筆形態 共著
掲載誌名 PLoS ONE
掲載区分国外
出版社・発行元 Public Library of Science
巻・号・頁 9(5),pp.e98014
著者・共著者 Takeda Y. Yamanaka K. Yamagishi N. Sato M.
概要 Brain activities related to cognitive functions, such as attention, occur with unknown and variable delays after stimulus onsets. Recently, we proposed a method (Common Waveform Estimation, CWE) that could extract such brain activities from magnetoencephalography (MEG) or electroencephalography (EEG) measurements. CWE estimates spatiotemporal MEG/EEG patterns occurring with unknown and variable delays, referred to here as unlocked waveforms, without hypotheses about their shapes. The purpose of this study is to demonstrate the usefulness of CWE for cognitive neuroscience. For this purpose, we show procedures to estimate unlocked waveforms using CWE and to examine their role. We applied CWE to the MEG epochs during Go trials of a visual Go/NoGo task. This revealed unlocked waveforms with interesting properties, specifically large alpha oscillations around the temporal areas. To examine the role of the unlocked waveform, we attempted to estimate the strength of the brain activity of the unlocked waveform in various conditions. We made a spatial filter to extract the component reflecting the brain activity of the unlocked waveform, applied this spatial filter to MEG data under different conditions (a passive viewing, a simple reaction time, and Go/NoGo tasks), and calculated the powers of the extracted components. Comparing the powers across these conditions suggests that the unlocked waveforms may reflect the inhibition of the task-irrelevant activities in the temporal regions while the subject attends to the visual stimulus. Our results demonstrate that CWE is a potential tool for revealing new findings of cognitive brain functions without any hypothesis in advance.
DOI 10.1371/journal.pone.0098014