Figure 4. θ-band phase lag and α-θ power-phase coupling in RT time courses. A, Top, The 0–2 Hz filtered RT time courses as a function of cue-to-target SOA for valid (red) and invalid (black) conditions. Middle, θ-band (2–5 Hz) filtered RT time courses in LVF, with dotted box indicating the time range (0.4–1.1 s) for further phase lag analysis. Bottom, Power response for α-band (8–20 Hz) filtered RT time courses in LVF, with dotted box indicating the time range (0.3–1.0 s) for further phase-power locking analysis. B, Polar plots for the distribution (n = 49) of θ-band (2–5 Hz) phase lag between valid and invalid conditions in the RT time courses in LVF during the time range (A, middle, dotted box, 0.4–1.1 s). Red line indicates the mean valid–invalid θ phase difference. C, Phase-power locking in RT time course during the time range (A, bottom, dotted box, 0.3–1.0 s). Left, Grand mean cross-frequency phase-power locking (n = 49). Middle, Grand mean power response (n = 49) as a function of frequency (4–20 Hz) and θ-band phase (−180° to 180°). Dotted line indicates the upper and lower boundary for α-band range (8–20 Hz). Right, Grand mean (n = 49, mean ± SEM) α-band power (8–20 Hz, range between two dotted lines in left panel) as a function of θ-band (2–5 Hz) phase (−180° to 180°) for valid (red) and invalid (black) conditions, when target was presented in LVF (upper) or RVF (lower).