title: Prefrontal cortex modulates placebo analgesia.
abstract: Expectations and beliefs modulate the experience of pain, which is particularly evident in placebo analgesia. The dorsolateral prefrontal cortex (DLPFC) has been associated with pain regulation and with the generation, maintenance and manipulation of cognitive representations, consistent with its role in expectation. In a heat-pain paradigm, we employed non-invasive low-frequency repetitive transcranial magnetic stimulation (rTMS) to transiently disrupt left and right DLPFC function or used the TMS device itself as a placebo, before applying an expectation-induced placebo analgesia. The results demonstrated that placebo significantly increased pain threshold and pain tolerance. While rTMS did not affect pain experience, it completely blocked placebo analgesia. These findings suggest that expectation-induced placebo analgesia is mediated by symmetric prefrontal cortex function.
authors.affiliation: Collegium Helveticum, Schmelzbergstrasse 25, CH-8092 Zurich, Switzerland Institute of Medical Psychology and Behavioral Immunobiology, University Clinic Essen, 45122 Duisburg-Essen, Germany Department of Psychology, University of Cape Town, Rondebosch 7701, South Africa.
authors.forename: Peter
authors.initials: P
authors.lastname: Krummenacher
authors.forename: Victor
authors.initials: V
authors.lastname: Candia
authors.forename: Gerd
authors.initials: G
authors.lastname: Folkers
authors.forename: Manfred
authors.initials: M
authors.lastname: Schedlowski
authors.forename: Georg
authors.initials: G
authors.lastname: Schönbächler
mesh_terms: D000328:Adult; D000339:Affect / Q000187:drug effects; D000698:Analgesia / Q000379:methods* / Q000523:psychology*; D000704:Analysis of Variance; D006801:Humans; D008297:Male; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000187:drug effects*; D010812:Physical Stimulation / Q000009:adverse effects; D015990:Placebo Effect; D010919:Placebos / Q000494:pharmacology*; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000502:physiology*; D011795:Surveys and Questionnaires; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult
chemical_list: D010919:Placebos