title: Relative valuation of pain in human orbitofrontal cortex.
abstract: The valuation of health-related states, including pain, is a critical issue in clinical practice, health economics, and pain neuroscience. Surprisingly the monetary value people associate with pain is highly context-dependent, with participants willing to pay more to avoid medium-level pain when presented in a context of low-intensity, rather than high-intensity, pain. Here, we ask whether context impacts upon the neural representation of pain itself, or alternatively the transformation of pain into valuation-driven behavior. While undergoing fMRI, human participants declared how much money they would be willing to pay to avoid repeated instances of painful cutaneous electrical stimuli delivered to the foot. We also implemented a contextual manipulation that involved presenting medium-level painful stimuli in blocks with either low- or high-level stimuli. We found no evidence of context-dependent activity within a conventional "pain matrix," where pain-evoked activity reflected absolute stimulus intensity. By contrast, in right lateral orbitofrontal cortex, a strong contextual dependency was evident, and here activity tracked the contextual rank of the pain. The findings are in keeping with an architecture where an absolute pain valuation system and a rank-dependent system interact to influence willing to pay to avoid pain, with context impacting value-based behavior high in a processing hierarchy. This segregated processing hints that distinct neural representations reflect sensory aspects of pain and components that are less directly nociceptive whose integration also guides pain-related actions. A dominance of the latter might account for puzzling phenomena seen in somatization disorders where perceived pain is a dominant driver of behavior.
authors.affiliation: Wellcome Trust Centre for Neuroimaging at UCL, London WC1N 3BG, United Kingdom, UCL Institute of Cognitive Neuroscience, London WC1N 3AR, United Kingdom, joel.winston@ucl.ac.uk.
authors.forename: Joel S
authors.identifier: http://orcid.org/0000-0002-3957-0612
authors.initials: JS
authors.lastname: Winston
authors.affiliation: Department of Surgery & Cancer, Imperial College, London W2 1PG, United Kingdom, Warwick Business School, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: Ivo
authors.initials: I
authors.lastname: Vlaev
authors.affiliation: Center for Information and Neural Networks, Osaka 565-0871, Japan, Computational and Biological Learning Laboratory, Department of Engineering, Cambridge University, Cambridge CB2 1PZ, United Kingdom, and.
authors.forename: Ben
authors.initials: B
authors.lastname: Seymour
authors.affiliation: Warwick Business School, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: Nick
authors.identifier: http://orcid.org/0000-0002-9745-0686
authors.initials: N
authors.lastname: Chater
authors.affiliation: Wellcome Trust Centre for Neuroimaging at UCL, London WC1N 3BG, United Kingdom, Max Planck UCL Centre for Computational Psychiatry and Ageing Research, London WC1B 5EH, United Kingdom.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Dolan
mesh_terms: D000328:Adult; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D010146:Pain / Q000503:physiopathology*; D058748:Pain Perception / Q000502:physiology*; D017397:Prefrontal Cortex / Q000503:physiopathology*; D055815:Young Adult
keywords: context sensitivity; neuroeconomics; pain; subjective health complaints; valuation