title: Placebo analgesia affects brain correlates of error processing.
abstract: Placebo analgesia (PA) is accompanied by decreased activity in pain-related brain regions, but also by greater prefrontal cortex (PFC) activation, which has been suggested to reflect increases in top-down cognitive control and regulation of pain. Here we test whether PA is associated with altered prefrontal monitoring functions that could adjust nociceptive processing to a mismatch between expected and experienced pain. We recorded event-related potentials to response errors in a go/nogo task during placebo vs. a matched control condition. Error commission was associated with two well-described components, the error-related negativity (ERN) and the error positivity (Pe). Results show that the Pe, but not the ERN, was amplified during placebo analgesia compared to the control condition, with neural sources in the lateral and medial PFC. This Pe increase was driven by participants showing a placebo-induced change in pain tolerance, but was absent in the group of non-responders. Our results shed new light on the possible functional mechanisms underlying PA, suggesting a placebo-induced transient change in prefrontal error monitoring and control functions.
authors.affiliation: Laboratory for Neurology and Imaging of Cognition, Department of Neurosciences, University of Geneva, Switzerland. leonie.koban@unige.ch
authors.forename: Leonie
authors.initials: L
authors.lastname: Koban
authors.forename: Marcel
authors.initials: M
authors.lastname: Brass
authors.forename: Margaret T
authors.initials: MT
authors.lastname: Lynn
authors.forename: Gilles
authors.initials: G
authors.lastname: Pourtois
mesh_terms: D000328:Adult; D000698:Analgesia; D001931:Brain Mapping; D015928:Cognitive Behavioral Therapy; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D059226:Nociceptive Pain / Q000188:drug therapy / Q000503:physiopathology; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology; D059408:Pain Management; D010919:Placebos / Q000008:administration & dosage*; D017397:Prefrontal Cortex / Q000187:drug effects; D011930:Reaction Time
chemical_list: D010919:Placebos