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Computational Intelligence and Neuroscience
Volume 2010, Article ID 329436, 12 pages
http://dx.doi.org/10.1155/2010/329436
Research Article

Independent Component Analysis for Source Localization of EEG Sleep Spindle Components

1Department of Medical Instrumentation Technology, Technological Educational Institution of Athens, Ag. Spyridonos Street, Egaleo,12210 Athens, Greece
2Sleep Research Unit, Eginition Hospital, Department of Psychiatry, University of Athens, 74 Vas.Sophias Avenue, 11528 Athens, Greece

Received 15 June 2009; Revised 24 November 2009; Accepted 19 January 2010

Academic Editor: Sara Gonzalez Andino

Copyright © 2010 Erricos M. Ventouras et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Sleep spindles are bursts of sleep electroencephalogram (EEG) quasirhythmic activity within the frequency band of 11–16 Hz, characterized by progressively increasing, then gradually decreasing amplitude. The purpose of the present study was to process sleep spindles with Independent Component Analysis (ICA) in order to investigate the possibility of extracting, through visual analysis of the spindle EEG and visual selection of Independent Components (ICs), spindle “components” (SCs) corresponding to separate EEG activity patterns during a spindle, and to investigate the intracranial current sources underlying these SCs. Current source analysis using Low-Resolution Brain Electromagnetic Tomography (LORETA) was applied to the original and the ICA-reconstructed EEGs. Results indicated that SCs can be extracted by reconstructing the EEG through back-projection of separate groups of ICs, based on a temporal and spectral analysis of ICs. The intracranial current sources related to the SCs were found to be spatially stable during the time evolution of the sleep spindles.