Placebo and nocebo effects, positive and negative effects experienced after both real and sham interventions, putatively due to positive or negative outcome expectancies, can shape our sensory... Show morePlacebo and nocebo effects, positive and negative effects experienced after both real and sham interventions, putatively due to positive or negative outcome expectancies, can shape our sensory experience. Although placebo and nocebo effects are known to occur reliably in many individuals for sensations like pain and itch, our understanding of psychological learning processes and methodological factors that influence these effects remains limited. Chapters 2, 3, and 4 investigate this topic with meta-analysis, narrative review, and a behavioral study. Similarly, our characterization of the neural markers of nocebo effects is incomplete. A better grasp of how these effects form is necessary to contextualize them within the larger framework of bottom-up and top-down integration. Chapters 5, 6, and 7 investigate this topic in a series of EEG and fMRI studies. Advancing both psychological and neural accounts of placebo and nocebo effects will aid in applying findings from this field of study to everyday life; particularly in clinical settings, and potentially any setting in which expectations regarding one’s future experiences come into play. Show less
This PhD research dealt with neurobiological and behavioral aspects of pain. Previous research has demonstrated that pain sensitivity can be worsened as a result of learned negative expectations, a... Show moreThis PhD research dealt with neurobiological and behavioral aspects of pain. Previous research has demonstrated that pain sensitivity can be worsened as a result of learned negative expectations, a phenomenon termed nocebo hyperalgesia –a counterpart to placebo analgesia. This PhD dissertation describes neuroimaging and biobehavioral experimental studies as well as a review and a meta-analysis concerned with such learned effects on pain. The research adds to a growing literature that has been challenging antiquated understandings of pain as a bottom-up process. We conducted a series of biobehavioral studies to further our understanding of how bottom-up pain signaling can be influenced by top-down processing. We examined the types of experiences, such as receiving negative information or experiencing a negative effect first-hand, that may lead to stronger nocebo effects. Behavioral paradigms were used to model real-life pain experiences, through validated methods, novel learning manipulations, as well as a close examination of emotional correlates such as fear. Concurrently, innovative neuroscientific methods –including pharmacological manipulations– were used to examine the biobehavioral underpinnings of learned nocebo responses. Our findings add to the growing knowledgebase from the field of nocebo hyperalgesia, demonstrating that learning by experience can decisively influence the processing and perception of noxious stimuli. Show less
