title: Modulation of pain ratings by expectation and uncertainty: Behavioral characteristics and anticipatory neural correlates.
abstract: Expectations about the magnitude of impending pain exert a substantial effect on subsequent perception. However, the neural mechanisms that underlie the predictive processes that modulate pain are poorly understood. In a combined behavioral and high-density electrophysiological study we measured anticipatory neural responses to heat stimuli to determine how predictions of pain intensity, and certainty about those predictions, modulate brain activity and subjective pain ratings. Prior to receiving randomized laser heat stimuli at different intensities (low, medium or high) subjects (n=15) viewed cues that either accurately informed them of forthcoming intensity (certain expectation) or not (uncertain expectation). Pain ratings were biased towards prior expectations of either high or low intensity. Anticipatory neural responses increased with expectations of painful vs. non-painful heat intensity, suggesting the presence of neural responses that represent predicted heat stimulus intensity. These anticipatory responses also correlated with the amplitude of the Laser-Evoked Potential (LEP) response to painful stimuli when the intensity was predictable. Source analysis (LORETA) revealed that uncertainty about expected heat intensity involves an anticipatory cortical network commonly associated with attention (left dorsolateral prefrontal, posterior cingulate and bilateral inferior parietal cortices). Relative certainty, however, involves cortical areas previously associated with semantic and prospective memory (left inferior frontal and inferior temporal cortex, and right anterior prefrontal cortex). This suggests that biasing of pain reports and LEPs by expectation involves temporally precise activity in specific cortical networks.
authors.affiliation: Human Pain Research Group, Clinical Sciences Building, Hope Hospital, Salford M6 8HD, United Kingdom Wellcome Department of Imaging Neuroscience, Functional Imaging Laboratory, 12 Queen Square, London WC1N 3BG, United Kingdom School of Psychological Sciences, University of Manchester, Zochonis Building, Oxford Road, Manchester M13 9PL, United Kingdom.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Brown
authors.forename: Ben
authors.initials: B
authors.lastname: Seymour
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Boyle
authors.forename: Wael
authors.initials: W
authors.lastname: El-Deredy
authors.forename: Anthony K P
authors.initials: AKP
authors.lastname: Jones
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D001519:Behavior / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D003463:Cues; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007834:Lasers; D008568:Memory / Q000502:physiology; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology*; D009483:Neuropsychological Tests; D010146:Pain / Q000523:psychology*; D010147:Pain Measurement / Q000379:methods / Q000523:psychology*; D017288:Pain Threshold / Q000502:physiology; D010812:Physical Stimulation; D035501:Uncertainty