Figure 1. A, Condition-averaged power spectra of individual participants (N = 14; gray lines) based on data from Keitel et al. (2013). Heavy yellow lines depict the Grand Average spectrum. Data were preprocessed as described in the original study but epochs were subjected to Fourier transforms before averaging to retain oscillatory neural activity not phase-locked to stimulation. Narrow-band peaks at F1 = 10.7 Hz and F2 = 14.2 Hz correspond to stimulation frequencies in left and right hemifields, respectively. Inset magnifies 9–11 Hz. Broader peaks, here denoted with α, are visible adjacent to F1. B, α subband (10 ± 0.25 Hz; denoted by *) power and F1 SSR power topographies for the five participants exhibiting maximal α* power. Black dots indicate the electrode cluster from which spectra were calculated. Note different scales. C, Adapted from Spaak et al. (2014) (with permission). Grand Average event-related field elicited by a left (blue) or right hemifield (red) 10 Hz stimulus train. The oscillation reverberates after the last stimulus offset (dashed gray line). D, Grand Average event-related potential (N = 19; electrodes POz, O1, Oz, O2, Iz; two-pass finite impulse response filter: 256-point Blackman window, pass band 22–26 Hz) derived from data of Porcu et al. (2014). Here, a visual stimulus train presented at a rate of 24 Hz for ∼1.4 s elicited an SSR (black line) that reverberates after offset of the last stimulus. Blue line depicts ERP from a condition without rhythmic visual stimulation. Last stimulus offset is at 1396 ms (dashed gray line). E, Hilbert amplitude difference time course (heavy red line) derived from waveforms in D. Waveform envelopes were calculated by means of Hilbert transforms for each electrode and participant, then averaged for flicker-present and flicker-absent conditions. Subtracting flicker-absent from flicker-present yielded the depicted time course. Black lines illustrate upper and lower 95%-confidence limits of a running t test against zero (two-tailed). At # (1635 ms; for a stricter 99%-confidence limit: 1615 ms), the lower bound crosses zero, indicating the oscillation's decay.