biostudies-literaturePohle LGDeutsche Forschungsgemeinschaft (DFG)European Research CouncilEC | H2020 | PRIORITY 'Excellent science' | H2020 European Research Council (ERC)Max Planck Society1244-1256https://www.ebi.ac.uk/biostudies/studies/S-EPMC7618183biostudies-literatureUnknown134(4)Repetition suppression, the reduced neural response upon repeated presentation of a stimulus, can be explained by models focusing on bottom-up (i.e., adaptation) or top-down (i.e., expectation) mechanisms. Predictive coding models fall into the latter category and propose that repetitions are expected and therefore elicit smaller prediction error responses. Although studies in the visual and auditory domain provide some support for such models, in nociception evidence remains inconclusive, despite the substantial influence expectations exert on pain perception. To assess expectation effects on repetition suppression in nociception, we developed a paradigm in which healthy volunteers received brief CO₂ laser stimuli, while we acquired electroencephalographic (EEG) and peripheral physiological data. Importantly, laser stimuli could be either repeated after one second or not be repeated, with the probability of repetitions manipulated in a block-wise fashion, such that repetitions were either expected or unexpected. We observed repetition suppression in laser-evoked potentials and laser-induced gamma band oscillations, but not in laser-induced desynchronizations in the alpha and beta band. Critically, neither these EEG responses, nor the peripheral physiological data showed significant differences between the expectation conditions, with Bayesian analyses mostly providing evidence for an absence of effects. This indicates that repetition suppression to brief nociceptive laser stimuli is not driven by top-down factors, but rather mediated by other adaptation processes. Although this does not preclude an influence of predictive coding models in nociception, it suggests that when the nervous system receives highly precise input, its responses are less susceptible to influence from expectations.<b>NEW & NOTEWORTHY</b> We show that repetition suppression (RS; the diminished neural activity upon repeated stimulus presentation) can be observed in the nociceptive domain: brief laser stimuli lead to RS in event-related potentials and gamma oscillations. Importantly, nociceptive RS is not modulated by repetition probability and thus expectations regarding the occurrence of a repetition. This indicates that nociceptive responses are less prone to top-down expectations under conditions of limited sensory uncertainty, as established via precise laser stimuli.Journal of neurophysiologyExpectation effects on repetition suppression in nociception.PMC7618183PL321/14-1758974Nierula BPohle LGNickel MMPloner MEippert FHorn UfalseExpectation effects on repetition suppression in nociception.Repetition suppression, the reduced neural response upon repeated presentation of a stimulus, can be explained by models focusing on bottom-up (i.e., adaptation) or top-down (i.e., expectation) mechanisms. Predictive coding models fall into the latter category and propose that repetitions are expected and therefore elicit smaller prediction error responses. Although studies in the visual and auditory domain provide some support for such models, in nociception evidence remains inconclusive, despite the substantial influence expectations exert on pain perception. To assess expectation effects on repetition suppression in nociception, we developed a paradigm in which healthy volunteers received brief CO₂ laser stimuli, while we acquired electroencephalographic (EEG) and peripheral physiological data. Importantly, laser stimuli could be either repeated after one second or not be repeated, with the probability of repetitions manipulated in a block-wise fashion, such that repetitions were either expected or unexpected. We observed repetition suppression in laser-evoked potentials and laser-induced gamma band oscillations, but not in laser-induced desynchronizations in the alpha and beta band. Critically, neither these EEG responses, nor the peripheral physiological data showed significant differences between the expectation conditions, with Bayesian analyses mostly providing evidence for an absence of effects. This indicates that repetition suppression to brief nociceptive laser stimuli is not driven by top-down factors, but rather mediated by other adaptation processes. Although this does not preclude an influence of predictive coding models in nociception, it suggests that when the nervous system receives highly precise input, its responses are less susceptible to influence from expectations.<b>NEW & NOTEWORTHY</b> We show that repetition suppression (RS; the diminished neural activity upon repeated stimulus presentation) can be observed in the nociceptive domain: brief laser stimuli lead to RS in event-related potentials and gamma oscillations. Importantly, nociceptive RS is not modulated by repetition probability and thus expectations regarding the occurrence of a repetition. This indicates that nociceptive responses are less prone to top-down expectations under conditions of limited sensory uncertainty, as established via precise laser stimuli.2025-01-01T00:00:00Z2025 Oct2026-06-04T11:56:02.256Z2026-05-08T03:11:27.776ZS-EPMC76181834092935410.1152/jn.00359.2025