Table 4.

Pairwise comparisons of spectral exponents among the four ROIs in the two analyzed frequency ranges (20-35 Hz and 80-150 Hz)^a

Comparison	df	t (20-35 Hz)	p (20-35 Hz)	t (80-150 Hz)	p (80-150 Hz)
CTX-ENT	192	2.557	0.054	1.551	0.408
CTX-HIP	198	12.421	4.34 × 10−14	−14.214	4.31 × 10−14
CTX-AMY	184	11.409	5.35 × 10−14	1.631	0.363
ENT-HIP	82	7.591	3.63 × 10−12	−12.321	4.35 × 10−14
ENT-AMY	68	7.564	4.27 × 10−12	0.195	0.997
HIP-AMY	74	0.608	0.929	11.650	4.90 × 10−14

^aThe first column lists each of the six pairwise comparisons, the second one the relative degrees of freedom (df) of the test, the third and fourth ones the t values and p values of the post hoc t test for the 20-35 Hz range, respectively, and the last two columns the t values and p values for the 80-150 Hz range, respectively. All pairs of cortical-limbic areas have significant differences in their 20-35 Hz exponent, while the difference between temporal and entorhinal cortex is slightly below significance threshold. For the 80-150 Hz range, only the comparisons between hippocampus and the other areas are significant because of the very steep slope of hippocampal electrodes in the high-γ range. The spectral exponent values are computed through a mixed-effects model with a patient-specific random effect. p values are corrected for multiple comparisons via the Tukey range test.