Figure 5.

Plots with gray background show the individual difference (ketamine − placebo) of the logarithmic EEG Power (Δln[FFT_P]) against the matching individual difference of default mode network functional connectivity (Δconnectivity). Plots with white background show the individual ln(FFT_P) against corresponding functional connectivity for placebo (black) and ketamine condition (red) with associated linear regressions (lines). (a) For delta, an increase in Δln(FFT_P) of electrode CP5 is significantly accompanied with an increased Δ in left IPL‐PCC/precuneus functional connectivity with a Pearson's R of 0.52 (p = .032). This is related to the right shifted parallel offset of the linear regression of ketamine condition shown in (b) with higher FFT_P and functional connectivity values for ketamine condition. (c, d) A comparable analysis of theta for C4 electrode and DMN functional connectivity between mPFC and PCC/precuneus shows a trend‐wise negative correlation for Δ analysis with a significant decreased correlation for placebo condition (R = −0.635, p = .006). For ketamine condition, a floor effect with connectivity values close to zero could be observed which leads to low Pearson's R of −0.296 (p = .249). (e, f) Analyzing ln(FFT_P) of gamma for electrode Fz against DMN functional connectivity of mPFC, comparable results with a significant negative correlation for Δ analysis and a trend‐wise negative correlation between ln(FFT_P) and functional connectivity for placebo condition could be seen. Because of the aforementioned floor effect of ketamine related DMN functional connectivity of mPFC, a correlation between ln(FFT_P) and DMN functional connectivity for ketamine condition could not be observed