BCI feature discriminancy.

<p><b>(A)</b> Topographic maps of discriminancy per training month on the 16 EEG channel locations over the sensorimotor cortex monitored. Bright color indicates high discriminancy between Both Hands and Both Feet MI tasks employed by both pilots (P1 top, P2 bottom). The discriminancy of each channel is quantified as the Fisher score of the EEG signal's power spectral density distributions for these two mental classes in the high β-band (22–32 Hz) within each run. Each map illustrates local Fisher scores (with interchannel interpolation) averaged over all runs within the supertitled month. <b>(B)</b> Average medial (blue, channels: FCz, Cz, CPz) and lateral (red, channels: FC3, C3, CP3, FC4, C4, CP4) discriminancy for all performed offline, online, and racing runs of pilots P1 and P2. The corresponding linear fits and Pearson correlation coefficients (significance tested with Student <i>t</i> test distribution) are reported to indicate training effects. Vertical dashed lines indicate the training session during which each run took place. <b>(C)</b> Average and standard deviations of medial region (blue) and lateral region (red) discriminancy within the first and last four runs of training for pilots P1 and P2. Statistically significant differences are shown with two-sided Wilcoxon ranksum tests, (**): <i>p</i> < .01, (***): <i>p</i> < .001. Fig 4 data is located at <a href="https://doi.org/10.5281/zenodo.1205702" target="_blank">https://doi.org/10.5281/zenodo.1205702</a>, <a href="https://doi.org/10.5281/zenodo.1205704" target="_blank">https://doi.org/10.5281/zenodo.1205704</a>, <a href="https://doi.org/10.5281/zenodo.1205708" target="_blank">https://doi.org/10.5281/zenodo.1205708</a>. BCI, brain–computer interface; EEG, electroencephalography; MI, motor imagery.