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Computational Intelligence and Neuroscience
Volume 2010, Article ID 785279, 8 pages
Research Article

Cross-Correlation of Motor Activity Signals from dc-Magnetoencephalography, Near-Infrared Spectroscopy, and Electromyography

1Division of Medical Physics, Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
2Department of Neurology, Charité Campus Benjamin Franklin, 12200 Berlin, Germany
3Department of Neurology, Vivantes Auguste Viktoria Klinikum, 12157 Berlin, Germany

Received 16 June 2009; Accepted 26 October 2009

Academic Editor: Laura Astolfi

Copyright © 2010 Tilmann H. Sander 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.


Neuronal and vascular responses due to finger movements were synchronously measured using dc-magnetoencephalography (dcMEG) and time-resolved near-infrared spectroscopy (trNIRS). The finger movements were monitored with electromyography (EMG). Cortical responses related to the finger movement sequence were extracted by independent component analysis from both the dcMEG and the trNIRS data. The temporal relations between EMG rate, dcMEG, and trNIRS responses were assessed pairwise using the cross-correlation function (CCF), which does not require epoch averaging. A positive lag on a scale of seconds was found for the maximum of the CCF between dcMEG and trNIRS. A zero lag is observed for the CCF between dcMEG and EMG. Additionally this CCF exhibits oscillations at the frequency of individual finger movements. These findings show that the dcMEG with a bandwidth up to 8 Hz records both slow and faster neuronal responses, whereas the vascular response is confirmed to change on a scale of seconds.