Figure 4
From: An EEG-based study of discrete isometric and isotonic human lower limb muscle contractions
Grand average normalized spectrograms for supplementary motor area electrocortical sources showing average changes in spectral power during the task relative to a pre-trial baseline for isometric (left) versus isotonic (middle) trials. The right panel shows the difference between isometric and isotonic conditions. The horizontal axis begins 1 s prior to trial onset (To; first black vertical line) and ends 1 s after trial offset (Tf; second black vertical line). The times between the onset and offset of the trials were warped to align these latencies across all trials. Non-significant changes from baseline (p > 0.05) were set to 0 dB (green).