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 2008/07
形態種別 学術雑誌
標題 Extracting a stimulus-unlocked component from EEG during NoGo trials of Go/NoGo task
執筆形態 共著
掲載誌名 NeuroImage
出版社・発行元 Elsevier Inc.
巻・号・頁 41(3),pp.777-788
著者・共著者 Takeda Y. Yamanaka K. Nozaki D. Yamamoto Y.
概要 Like electroencephalographic (EEG) activity during reaction time tasks, EEG activity during tasks without overt responses may also consist of two components: stimulus-locked and -unlocked components. The extraction of such stimulus-unlocked components has been difficult owing to the unknown delays. Here, we propose a novel method to extract both of the two components from single-channel EEG epochs. In this method, we initially set random values for the delays and extract uncontaminated stimulus-locked and -unlocked components using the preset delays and a discrete Fourier transform. Then, we reconstruct the EEG by overlapping the extracted components with the preset delays, and calculate the residual errors between the reconstructed and original EEG. This procedure is repeated by updating the delays until the residual errors become adequately small. After verifying the performance of this method by two kinds of simulations with artificial and EEG data, we apply the method to EEG during NoGo trials of a Go/NoGo task, and obtain the stimulus-unlocked components, the magnitudes of which are comparable with those of the stimulus-locked components. By applying this method, it is possible to study internal and subjective brain activity, which occurs with variable delays.
DOI 10.1016/j.neuroimage.2008.03.012