Figure 3
EEG coherence following tDCS during REM sleep. Inter-hemispheric EEG coherence between frontal (top), temporal (middle), and parietal (bottom) electrodes surrounding the tDCS site, expressed as a difference between sham-stimulation and tDCS conditions (Δ-coherence). Jittered circles represent individual participants. Red lines depict the mean of Δ-coherence, pink bars represent 1 standard deviation (SD), and blue bars represent 95% confidence intervals for the mean. Positive values indicate higher coherence in the sham-stimulation condition, whereas negative values indicate higher coherence in the tDCS condition. Δ-coherence is plotted separately in four stimulation-free time intervals preceding controlled awakenings from REM sleep. In the parietal region, coherence was reduced by tDCS compared to sham stimulation in −60- to 46 sec (Z = 2.5, p = 0.013, r = 0.79), −45 to −31 sec (t(9) = 3.17, p = 0.011, d = 0.97), −30 to −16 sec (t(9) = 2.27, p = 0.05, d = 0.88) and −15 to −1 sec (t(9) = 2.57, p = 0.03, d = 0.74) time intervals. * p < 0.05.
