Electrophysiological Correlates of Nocebo Effects on Pain

Pain is a nociceptive somatosensory process that can arise as a debilitating and chronic symptom in various diseases or following an injury. How pain is experienced can vary widely within and across individuals, and can be shaped by cognitive processes such as learning. Nocebo effects, negative changes in symptom severity attributed to learned outcome-expectations, demonstrate how learning processes can be detrimental for the experience of pain. Research to date has produced inconclusive findings regarding the electrophysiological correlates on nocebo effects. The few studies that have applied electroencephalography (EEG) in this field have pointed towards a potential involvement of alpha-band activity, but the direction of this involvement remains unclear. For example, an EEG study of conditioned nocebo hyperalgesia found a pre to post increase in resting state alpha band power that was correlated with pain catastrophizing scores and not with the magnitude of the nocebo effect. Later, other studies also found pre to post changes in alpha band power, however, these changes were correlated with the magnitude of nocebo effects and not pain catastrophizing. Given the discrepancy in findings, in this study the investigators plan to primarily investigate whether EEG components predict the magnitude of nocebo responses to thermal-pain stimuli. The investigators will also explore electrophysiological correlates during pain anticipation and whether nocebo responses would be significantly related to spectral and temporal EEG biomarkers. This study will utilize a validated model of instructional and associative learning methods (i.e., negative suggestions and classical conditioning, respectively) to experimentally induce nocebo effects on heat-evoked pain. Developing objective, brain-derived markers for nocebo responses, or the detection of individuals most susceptible to nocebo hyperalgesia, will aid in the comprehensive management of pain. This study is conducted at Leiden