Fig. 8

Comparison: DA contribution of frequency bands obtained in 2020 for final days of the BCI training period (sessions 19–21) vs. pre-competition days (sessions 22–24). Time-varying frequency maps indicating frequency range providing the highest level of contribution for 2-class classification using datasets recorded in 2020 for final days of the BCI training period (sessions 19–21) (A) and for the pre-competition days (sessions 22–24) (B). The absolute value of the difference in (A) and (B) frequency maps is indicated in (C)