Can Pain or Hyperalgesia Be a Classically Conditioned Response in Humans? A Systematic Review and Meta-Analysis

Abstract

The existing literature suggests that classical conditioning can amplify pain. No conclusions can be drawn about whether or not classical conditioning can elicit pain. Rigorous experimental conditioning studies with nociceptive unconditioned stimuli are needed to fill this gap in knowledge.

Learning by experience? Visceral pain‐related neural and behavioral responses in a classical conditioning paradigm

“…Findings support a distinct contribution of these limbic regions during anticipation in line with previous evidence documenting their role in pain‐related fear learning and memory processes, and in classically conditioned nocebo responses . In addition, they lend further support for the role of conditioned pain‐related anticipation as a mechanism in central pain modulation . In line with this assumption, we observed a strikingly similar activation pattern in response to cues that previously signaled highly intense stimulation and subsequent distension with overlapping neural activation particularly in a fronto‐limbic network involving pACC, dlPFC and caudate.…”

“…9 In addition, they lend further support for the role of conditioned pain-related anticipation as a mechanism in central pain modulation. 14,15 In line with this assumption, we observed a strikingly similar activation pattern in response to cues that previously signaled highly intense stimulation and subsequent distension with overlapping neural activation particularly in a fronto-limbic network involving F I G U R E 5 Region-of-interest (ROI) analyses of differential anticipatory neural activation during test [CS High > CS Low ]. Enhanced differential neural responses to cues predicting high intensity distensions in anterior PFC, thalamus and bilateral pACC, dlPFC, and caudate (all p FWE <.05).…”

“…Brain imaging studies addressing neural mechanisms underlying nocebo effects support an involvement of brain regions associated with sensory, cognitive, and emotional pain modulation . Some studies noted nocebo‐induced changes in neural activation also during mere pain anticipation, in keeping with the role of conditioned pain‐related fear . Accordingly, learned associations regarding previous pain‐related experiences established by instrumental or classical conditioning are considered key mechanisms in the formation of nocebo effects in pain …”

“…[6][7][8][9][10][11] Some studies noted View the podcast on this paper at the following sites: iTunes: https://itunes.apple.com/gb/podcast/ neurogastroenterology-motility-june-2017/ id1228083012 Youtube: https://youtu.be/4OT7zkYqG4s nocebo-induced changes in neural activation also during mere pain anticipation, 12,13 in keeping with the role of conditioned pain-related fear. 14,15 Accordingly, learned associations regarding previous painrelated experiences established by instrumental or classical conditioning are considered key mechanisms in the formation of nocebo effects in pain. 2,4 Although the clinical relevance of nocebo effects in the context of pain is indisputable, 2,5 studies addressing the underlying neural mechanisms have almost exclusively focused on negative expectations induced by verbal suggestions in experimental thermal [6][7][8]10,11 and visceral pain.…”

Defensive reflexes in people with pain – a biomarker of the need to protect? A meta-analytical systematic review

“…Indeed, a modern conceptualisation of pain (e.g. Moseley and Butler, 2015b) holds that pain is the end product of a complex evaluative process that is usually, but not necessarily, triggered by noxious stimuli (see Harvie et al (2015), Moseley (2004), and Moseley and Arntz (2007) for experimental evidence of the dissociation between nociception from pain and Madden et al (2015) for a systematic review of associative learning of pain). Thus, pain and lower reflex thresholds are more likely to reflect epiphenomena in much the same way as has been proposed for pain and motor control (Moseley, 2013).…”