Research Papers

Extracting task-related activation components from optical topography measurement using independent components analysis

[+] Author Affiliations
Takusige Katura, Hiroki Sato

Hitachi, Ltd., Advanced Research Laboratory, 2520 Akanuma, Hatoyama, Saitama 350-0395, Japan

Yutaka Fuchino

Kitasato University, Graduate School of Medical Sciences, 1-15-1 Kitasato Sagamihara, Kanagawa 228-8555, Japan

Takamasa Yoshida

Tokyo Institute of Technology, Department of Physical Electronics, Graduate School of Science and Engineering, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552, Japan

Hirokazu Atsumori, Masashi Kiguchi, Atsushi Maki

Hitachi, Ltd., Advanced Research Laboratory, 2520 Akanuma, Hatoyama, Saitama 350-0395, Japan

Masanori Abe

Tokyo Institute of Technology, Department of Physical Electronics, Graduate School of Science and Engineering, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552, Japan

Naoki Tanaka

Hitachi, Ltd., Advanced Research Laboratory, 2520 Akanuma, Hatoyama, Saitama 350-0395, Japan

J. Biomed. Opt. 13(5), 054008 (October 06, 2008). doi:10.1117/1.2981829
History: Received September 06, 2007; Revised April 10, 2008; Accepted April 14, 2008; Published October 06, 2008
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Optical topography (OT) signals measured during an experiment that used activation tasks for certain brain functions contain neuronal-activation induced blood oxygenation changes and also physiological changes. We used independent component analysis to separate the signals and extracted components related to brain activation without using any hemodynamic models. The analysis procedure had three stages: first, OT signals were separated into independent components (ICs) by using a time-delayed decorrelation algorithm; second, task-related ICs (TR-ICs) were selected from the separated ICs based on their mean intertrial cross-correlations; and third, the TR-ICs were categorized by k-means clustering into TR activation-related ICs (TR-AICs) and TR noise ICs (TR-NICs). We applied this analysis procedure to the OT signals obtained from experiments using one-handed finger-tapping tasks. In the averaged waveform of the TR-AICs, a small overshoot can be seen for a few seconds after the onset of each task and a few seconds after it ends, and the averaged waveforms of the TR-NICs have an N-shaped pattern.

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© 2008 Society of Photo-Optical Instrumentation Engineers

Citation

Takusige Katura ; Hiroki Sato ; Yutaka Fuchino ; Takamasa Yoshida ; Hirokazu Atsumori, et al.
"Extracting task-related activation components from optical topography measurement using independent components analysis", J. Biomed. Opt. 13(5), 054008 (October 06, 2008). ; http://dx.doi.org/10.1117/1.2981829


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