Fig. 1.

(A) FM stimuli for the EEG experiment. Periodicity was conveyed without fluctuations in amplitude (Top), but instead only by fluctuations in frequency (Middle). Listeners detected short silent gaps (Bottom Left) that were distributed uniformly around the 3-Hz FM cycle (Bottom Right); 2, 3, or 4 gaps were present in each 10-s stimulus. (B) Predicted neural and behavioral effects of entrainment to the FM stimulus. At stimulus onset (Top), the phase of the ongoing delta oscillation was predicted to reset to bring the neuronal oscillation into line with the driving stimulus (Middle), thereby modulating the excitation–inhibition cycle of the delta oscillation (Bottom Left). For this reason, gap detection hit rates were expected to be modulated by stimulus phase (Bottom Right).