The data were recorded from rat #1 and rat #2. Similar format as Fig. 1. a-b, h-i, Traces of LFP, raw (grey), filtered in theta (6–10 Hz, cyan) and eta (2.5–5.5 Hz, magenta) bands during high-speed (above 15 cm/s) running on track (top, i) and at low-speeds (below 15 cm/s) (bottom, ii) recorded on the same tetrodes in the same day RW (a, h) and VR (b, i). c, j, Amplitude envelope distribution during high- (30–60 cm/s) and low- (5–15 cm/s) speed runs for the theta (left panel) and eta (right panel) bands in RW. Theta amplitude was significantly (rat #1, p < 10−10, X2 = 822.14; rat #2, p < 10−10, X2 = 218.0, KW test) larger at high speeds than low speeds, whereas eta amplitude was slightly smaller at high speeds (rat #1, p = 10−10, X2 = 49.5; rat #2, p < 10−10, X2 = 359.5, KW test). d, k, Similar to c, but for VR showing large and significant increase in both eta (rat #1, p < 10−10, X2 = 7942.7; rat #2, p < 10−10, X2 = 279.76, KW test) and theta (rat #1, p < 10−10, X2 = 5542.9; rat #2, p < 10−10, X2 = 259.14, KW test) amplitudes at higher speeds. e, f, l, m, Power spectra of the example LFPs in RW (blue) and VR (red) during running (e, l) and immobility (f, m). g, n, Power index, during run compared to stop, showing prominent peaks in both eta and theta bands in VR (red) and only in theta band in RW (blue). (*** p < 10−10).