between 5.4 Hz ± 0.26 and 7.4 Hz ± 0.24 and increased linearly with increasing stimulus intensity (r = 0.64, p <0.001). The frequency of PFC 2–5 Hz oscillation varied between 2.7 Hz ± 0.19 and 3.7 Hz ± 0.3 (range: 1.9 – 5.1 Hz) and also increased linearly with increasing stimulus intensity (r = 0.37, p = 0.001) (Fig. 3D).