2.2.2.2. Induced ERD/ERS
The analysis of ERD/ERS data in the lower-1 α band showed a significant main effect of the factor group (F(3, 52) = 3.33; p < .027). The MM group showed lower-1 α ERS, whereas the other three groups showed lower-1 αERD. The difference was significant for the MS group (Tukey post hoc test p < .017). Also significant was the area by group interaction effect (F(6, 104) = 2.73; p < .024), revealing that the difference in ERD/ERS was more pronounced in the frontal and parieto-occipital areas. In both areas the MM group showed lower-1 α ERS, whereas the other three groups showed more lower-1 α ERD (see Fig. 5). To establish whether the lower-1 α band ERS/ERD significantly differed from zero a one-sample t-test was conducted. The t-test was significant for the MM (ERS) group (t(13) = 2.19; p < .047; M = −10.36; SD = 17.69); and the other three groups (ERD) (t(41) = 2.46; p < .018; M = 7.28; SD = 19.20).