Independent Component Analysis of Multi-channel Near-Infrared Spectroscopic Signals by Time-Delayed Decorrelation

  • Toshifumi Sano
  • Shuichi Matsuzaki
  • Yasuhiro Wada
Conference paper

DOI: 10.1007/978-3-642-15819-3_67

Part of the Lecture Notes in Computer Science book series (LNCS, volume 6352)
Cite this paper as:
Sano T., Matsuzaki S., Wada Y. (2010) Independent Component Analysis of Multi-channel Near-Infrared Spectroscopic Signals by Time-Delayed Decorrelation. In: Diamantaras K., Duch W., Iliadis L.S. (eds) Artificial Neural Networks – ICANN 2010. ICANN 2010. Lecture Notes in Computer Science, vol 6352. Springer, Berlin, Heidelberg

Abstract

Multi-channel near-infrared spectroscopy (NIRS) is increasingly used in empirical studies monitoring human brain activity. In a recent study, an independent component analysis (ICA) technique using time-delayed decorrelation was applied to NIRS signals since those signals reflect cerebral blood flow changes caused by task-induced responses as well as various artifacts. The decorrelation technique is important in NIRS-based analyses and may facilitate accurate separation of independent signals generated by oxygenated/deoxygenated hemoglobin concentration changes. We introduce an algorithm using time-delayed correlations that enable estimation of independent components (ICs) in which the number of components is fewer than that of observed sources; the conventional approach using a larger number of components may deteriorate settling of the solution. In a simulation, the algorithm was shown capable of estimating the number of ICs of virtually observed signals set by an experimenter, with the simulation reproducing seven sources where each was a mixture of three ICs and white noises. In addition, the algorithm was introduced in an experiment using ICs of NIRS signals observed during finger-tapping movements. Experimental results showed consistency and reproducibility of the estimated ICs that are attributed to patterns in the spatial distribution and temporal structure.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Toshifumi Sano
    • 1
  • Shuichi Matsuzaki
    • 1
  • Yasuhiro Wada
    • 1
  1. 1.Nagaoka University of TechnologyNiigataJapan

Personalised recommendations