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T. H. Sander, A. Liebert, M. Burghoff, H. Wabnitz, R. Macdonald, L. Trahms
Cross-correlation Analysis of the Correspondence between Magnetoencephalographic and Near-infrared Cortical Signals
Keywords: Direct current magnetoencephalography, near-infrared spectroscopy, independent component analysis, cross-correlation, neurovascular coupling
OBJECTIVES: The study of neurovascular coupling greatly benefits from combined measurements of neuronal and vascular signals. Two-step signal processing is developed to extract parameters describing the coupling. METHODS: Using a magnetometer in an extremely well shielded room a broadband magnetoencephalogram was simultaneously measured with time-resolved near-infrared spectroscopy during a motor activity paradigm. The raw MEG and NIRS data were denoised separately using independent component analysis. RESULTS: After averaging the resulting signals showed motor activity-related changes. The temporal correspondence between MEG and NIRS was assessed plotting a combined trajectory and calculating a cross-correlation. Compared to the MEG signal, at movement onset the NIRS signal showed an onset delay in the range of seconds. CONCLUSIONS: Multi-variate signal pre-processing followed by temporal delay estimates demonstrated the extraction of neurovascular coupling parameters.
Methods of Information in Medicine, Schattauer
Print ISSN: 0026-1270
Volume: 46, 01/2007
Pages: 164 - 168