Appendix 1—table 2. Results from the Shapiro-Wilk test for normality within each group and Levene’s test for homogeneity of variance across groups, for all dependent variables in the reported analyses.

The assumption of normality or homogeneity of variance was rejected if p was smaller than 0.05.

Dependent variable	Shapiro-Wilk test for normality				Levene’s Test for homogeneity of variance
	CC (W value)	CC (p-value)	SC (W value)	SC (p-value)	F(1,18)	p-value
Aperiodic intercept (EO)	0.86	0.076	0.98	0.975	0.48	0.499
Aperiodic slope (EO)	0.94	0.574	0.92	0.363	0.71	0.411
Aperiodic intercept (EC)	0.84	0.050	0.96	0.761	0.15	0.700
Aperiodic slope (EC)	0.88	0.141	0.93	0.431	0.64	0.434
Aperiodic intercept (LU)	0.94	0.526	0.95	0.650	0.00	0.993
Aperiodic slope (LU)	0.96	0.810	0.88	0.121	0.15	0.700
GABA+ (EC)	0.94	0.515	0.90	0.204	2.27	0.149
GABA+ (EO)	0.97	0.913	0.97	0.864	0.60	0.450
Glx (EC)	0.97	0.881	0.87	0.102	0.69	0.416
Glx (EO)	0.95	0.720	0.97	0.906	3.38	0.083
GABA+/Glx (EC)	0.96	0.834	0.94	0.501	2.07	0.172
GABA+/Glx (EO)	0.92	0.347	0.89	0.173	1.51	0.235