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. 1998 May 15;509(Pt 1):3–14. doi: 10.1111/j.1469-7793.1998.003bo.x

Figure 5. Coherence between EMGs and between EMGs and primary motor cortex local field potentials in a primate performing a steady pincer grip task.

Figure 5

A-C relate to first dorsal interosseous muscle (1DI); D-F relate to adductor pollici muscle (AdP). The bars at the top of the two columns indicate the range over which the amplifiers had a flat frequency response. A and D, EMG power spectra. A small ∼20 Hz peak is present in D. B and E, coherence between cortical slow wave and simultaneously recorded EMG from 1DI and AdP, respectively. C and F, coherence between cortical slow wave recording from a different cortical site and simultaneously recorded 1DI and AdP EMGs. Large values of coherence at 0 Hz (DC) have been removed. The insets in B-F represent cross-correlations between the slow wave and the EMG; the arrow indicates time zero. Scale bars are 20 ms, r= 0.01. G, coherence between simultaneously recorded EMGs from 1DI and AdP during a steady pincer grip. Coherence at ∼20 Hz is present between the cortical slow wave and EMGs from 1DI and AdP. Due to electrical cross-talk coherence is present between 1DI and AdP EMGs at all frequencies. However, a large peak is present at ∼20 Hz, the same frequency at which coherence is observed between the cortical slow wave and EMG. Compare, in this paper, Fig. 5G with Fig. 3B-C and Fig. 5B-F with Fig. 4E and G. (Reproduced from Baker et al. 1997.)