No effect of rhythmic visual stimulation on experimental pain perception

Abstract

Brain oscillations, particularly in the alpha, beta, and gamma bands, have been implicated in pain perception through correlational studies. Rhythmic visual stimulation (RVS) offers a noninvasive method to experimentally manipulate these oscillations and examine their potential role in pain perception. We conducted 2 within-participant experiments to assess whether RVS is associated with changes in both acute pain perception and pain-related neural oscillations. In experiment 1, 41 participants received brief (13 seconds) RVS at alpha (10 Hz), beta (18 Hz), or gamma (42 Hz) frequencies, or an arrhythmic control stimulation, while experiencing calibrated thermal pain with concurrent electroencephalography (EEG) recordings. Despite a successful increase of neural oscillations at targeted frequencies confirmed by EEG, pain-evoked oscillatory responses remained unchanged across brief RVS conditions in alpha, beta, and gamma bands. To replicate previous findings, experiment 2 extended experiment 1 by using longer RVS durations and phasic pain stimuli. Forty-nine new participants underwent 10-minute RVS at either 10 Hz or a 1-Hz control before rating electrical or laser pain stimuli. Across the 2 experiments, using different stimulation protocols and pain modalities, we found no evidence that RVS was associated with changes in acute pain perception or pain-related neural oscillations, with Bayesian analyses providing strong evidence for the null hypothesis. These null findings contrast with some previous reports but align with emerging mixed evidence in the literature, suggesting that the effects of RVS on pain may be less robust or more context-dependent than initially proposed.