Cross-correlation analysis of the correspondence between magnetoencephalographic and near-infrared cortical signals.
OBJECTIVE
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.
Sander
T H
TH
1Physikalisch-Technische Bundesanstalt, Division of Medical Physics, Berlin, Germany. tilmann.sander-thoemmes@ptb.de
Liebert
A
A
Burghoff
M
M
Wabnitz
H
H
Macdonald
R
R
Trahms
L
L
D002490:Central Nervous System / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography; D008962:Models, Theoretical; D009474:Neurons / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D015398:Signal Transduction / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D013223:Statistics as Topic; D013995:Time