Acoustic and electric stimulus phase alignment is the key experimental variable

Evidence

Target sounds were modulated at the tACS frequency (4 Hz) to give listeners the opportunity to sample the target at fixed phase angle on consecutive tACS cycles. … The critical parameter was the relative timing of acoustic and electric stimulation (Fig. 1a ). This phase lag was manipulated across six conditions by varying the onset of the target in steps of 41.7 ms (30°) across the 4-Hz tACS cycles. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4777

Categorization

• SEED: Angle: can rhythmic neural entrainment from external electric fields genuinely gate auditory perception at specific oscillation phases, or is this a methodological artifact of expectation?