title: Positive emotions and brain reward circuits in chronic pain.
abstract: Chronic pain is an important public health problem that negatively impacts the quality of life of affected individuals and exacts enormous socioeconomic costs. Chronic pain is often accompanied by comorbid emotional disorders including anxiety, depression, and possibly anhedonia. The neural circuits underlying the intersection of pain and pleasure are not well understood. We summarize recent human and animal investigations and demonstrate that aversive aspects of pain are encoded in brain regions overlapping with areas processing reward and motivation. We highlight findings revealing anatomical and functional alterations of reward/motivation circuits in chronic pain. Finally, we review supporting evidence for the concept that pain relief is rewarding and activates brain reward/motivation circuits. Adaptations in brain reward circuits may be fundamental to the pathology of chronic pain. Knowledge of brain reward processing in the context of pain could lead to the development of new therapeutics for the treatment of emotional aspects of pain and comorbid conditions.
authors.affiliation: Department of Pharmacology, Arizona Health Sciences Center, University of Arizona, Tucson, Arizona, 85721.
authors.forename: Edita
authors.initials: E
authors.lastname: Navratilova
authors.affiliation: Department of Pharmacology, Arizona Health Sciences Center, University of Arizona, Tucson, Arizona, 85721.|Pharmacology Research Laboratories II, Mitsubishi Tanabe Pharma Corporation, Saitama, 330-0854, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Morimura
authors.affiliation: Department of Pharmacology, Arizona Health Sciences Center, University of Arizona, Tucson, Arizona, 85721.
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Xie
authors.affiliation: Department of Research, Mayo Clinic, Scottsdale, Arizona, 85453.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Atcherley
authors.affiliation: Department of Pharmacology, Arizona Health Sciences Center, University of Arizona, Tucson, Arizona, 85721.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Ossipov
authors.affiliation: Department of Pharmacology, Arizona Health Sciences Center, University of Arizona, Tucson, Arizona, 85721.
authors.forename: Frank
authors.initials: F
authors.lastname: Porreca
mesh_terms: D000818:Animals; D001921:Brain / Q000503:physiopathology*; D059350:Chronic Pain / Q000503:physiopathology* / Q000523:psychology*; D004644:Emotions / Q000502:physiology*; D006801:Humans; D009434:Neural Pathways / Q000503:physiopathology; D012201:Reward
keywords: chronic pain; dopamine; emotions; motivation; opioids; reward circuits