Figure 5: Normalized coherence of all cortical area and muscle combinations in the beta band. The mean coherence was averaged across subjects and electrodes within the cortical area. BB: biceps brachii; BR: brachioradialis; TB: triceps brachii; Left: left cortical area; Right: right cortical area; Frontal: frontal cortical area; Central: central cortical area; Parietal: parietal cortical area. and .