Figure 2

Three metrics describe the spectral power changes induced in the tasks. The figure is divided into three columns, each for one metric. (a) Calculation of Induced Power (IP) from the mean band power change, which is represented in the area under the absolute mean band power change curve and obtained by summing the absolute values across time. (b) IP values for example active and inactive electrodes are presented as the plots for the mean band power change. Notice the IP values within the plots and in the summary below the plots. (c) Smoothness Score (SS) is calculated with one lag autocorrelation of the mean band power change in the low-theta (\({{\rm{SS}}}_{{{\rm{\theta }}}_{{\rm{l}}}}\)) and high-theta bands (\({{\rm{SS}}}_{{{\rm{\theta }}}_{{\rm{h}}}}\)). SS is the ordered sequence of elements (\({{\rm{SS}}}_{{{\rm{\theta }}}_{{\rm{l}}}}\), \({{\rm{SS}}}_{{{\rm{\theta }}}_{{\rm{h}}}}\)). (d) Two artificially generated examples of a smooth (sine) and a non-smooth (random uncorrelated Gaussian noise) signal with the corresponding 1-lag autocorrelation values. (e) Smoothness scores for the mean band power change of the low-theta band and high-theta band are shown for example active and inactive electrodes quantified with the autocorrelation values. (f) Gamma Consistency (GC) is calculated for an example electrode as pairwise absolute cross-correlation between the mean band power changes of the three gamma frequency ranges (low gamma, high gamma 1, and high gamma 2). The pairwise absolute cross-correlation values are sorted in descending order to get three features: GC₁, GC₂, and GC₃. GC is the ordered sequence of elements (GC₁, GC₂, GC₃). (g) Two artificially generated examples of pairs of signals and their cross-correlation values. The consistent pair has two in-phase sine waves, while the inconsistent pair has a sine wave and random uncorrelated Gaussian noise. (h) Mean band power change in the gamma ranges is presented for example active (on the left) and inactive (on the right) electrodes with the corresponding GC values. Notice the greater synchrony between the signals of the mean band power change for an active electrode compared to an inactive electrode. Subfigures (d,h) provide a quick reference to visually assess how the range of values obtained for a given metric compare to the artificial examples.