Table 2

Average correlation of high γ and HRV within region

Location	Number of bipolar channels	Number of patients	Sleep stage 1		Sleep stage 2		Sleep stage 3
Location	Number of bipolar channels	Number of patients	Mean z [95% CI]	p value	Mean z [95% CI]	p value	Mean z [95% CI]	p value
Anterior hippocampus	48	12	0.14 [0.1, 0.18]	2.2 × 10^-8	0.11 [0.064, 0.15]	8.2 × 10^-6	0.15 [0.089, 0.22]	2.6 × 10^-5
Posterior hippocampus	39	11	0.059 [0.016,0.1]	0.01	0.061 [0.019, 0.1]	0.0072	0.11 [0.044, 0.17]	0.0019
Cingulate	8	6	0.003 [−0.055, 0.061]	0.92	−0.0024 [−0.097,0.093]	0.96	0.083 [−0.033, 0.2]	0.21
Insula	5	4	0.043 [−0.09, 0.18]	0.56	−0.049 [−0.23, 0.13]	0.62	−0.18 [−0.51, 0.14]	0.33
Lateral temporal	46	13	0.083 [0.026, 0.14]	0.0068	−0.059 [−0.1, −0.017]	0.0081	−0.14 [−0.19, −0.081]	3 × 10^-5
Lateral occipital	10	6	0.029 [−0.032,0.09]	0.38	−0.032 [−0.12, 0.06]	0.52	0.044 [−0.12, 0.21]	0.61
Lateral parietal	52	14	0.084 [0.044, 0.12]	0.0001	−0.019 [−0.065, 0.026]	0.41	0.033 [−0.018, 0.084]	0.21
Medial occipito-parietal	28	11	−0.014 [−0.067, 0.04]	0.62	0.0014 [−0.054,0.057]	0.96	0.067 [0.0089, 0.13]	0.032
Medial temporo-occipital	24	10	0.018 [−0.047, 0.083]	0.59	−0.032 [−0.083, 0.018]	0.23	−0.052 [−0.094, −0.011]	0.022
Orbitofrontal	13	5	0.089 [0.031, 0.15]	0.011	0.10 [0.063, 0.14]	0.0003	0.041 [−0.09, 0.17]	0.55
Paracentral	19	9	−0.014 [−0.092, 0.063]	0.73	−0.04 [−0.12, 0.036]	0.32	0.002 [−0.07, 0.074]	0.97
Prefrontal	38	8	0.060 [0.022, 0.097]	0.0037	0.036 [−0.011, 0.083]	0.14	0.067 [0.025, 0.11]	0.0053

The correlation (r) was calculated between the normalized high γ and HRV measures (HGnorm and HFnorm) within each sleep stage, and averaged across all channels within each ROI. The Student’s t test was used to determine whether the mean Fisher z-transformed rvalues (z) differs from zero (FDR corrected p < 0.05).