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

Figure 3

Pairwise CCFs of the measured modalities using the continuous time series, that is, including all rest/move cycles, for time lags from 𝜏=−15 to 15 seconds. Note the different 𝑦-axis of the bottom figure. The highest correlations are reached for CCF(𝐵, EMGR) and the curve is fairly symmetric with respect to zero lag (𝜏=0 seconds). The correlations are slightly lower for CCF(𝐵,Δ𝐴) and the peak of the curve is shifted to positive 𝜏. Low correlations result for CCF(Δ𝐴, EMGR) and the peak of the curve is shifted to negative 𝜏.