title: Abnormal Brain Responses to Action Observation in Complex Regional Pain Syndrome.
abstract: Patients with complex regional pain syndrome (CRPS) display various abnormalities in central motor function, and their pain is intensified when they perform or just observe motor actions. In this study, we examined the abnormalities of brain responses to action observation in CRPS. We analyzed 3-T functional magnetic resonance images from 13 upper limb CRPS patients (all female, ages 31-58 years) and 13 healthy, age- and sex-matched control subjects. The functional magnetic resonance imaging data were acquired while the subjects viewed brief videos of hand actions shown in the first-person perspective. A pattern-classification analysis was applied to characterize brain areas where the activation pattern differed between CRPS patients and healthy subjects. Brain areas with statistically significant group differences (q < .05, false discovery rate-corrected) included the hand representation area in the sensorimotor cortex, inferior frontal gyrus, secondary somatosensory cortex, inferior parietal lobule, orbitofrontal cortex, and thalamus. Our findings indicate that CRPS impairs action observation by affecting brain areas related to pain processing and motor control.
  
  
  
  This article shows that in CRPS, the observation of others' motor actions induces abnormal neural activity in brain areas essential for sensorimotor functions and pain. These results build the cerebral basis for action-observation impairments in CRPS.
authors.affiliation: Systems and Clinical Neuroscience, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Aalto NeuroImaging, Aalto University School of Science, Espoo, Finland; Department of Neurology, Helsinki University Hospital, and Clinical Neurosciences, Neurology, University of Helsinki, Finland. Electronic address: jaakko.hotta@aalto.fi.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Hotta
authors.affiliation: Systems and Clinical Neuroscience, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Saari
authors.affiliation: Systems and Clinical Neuroscience, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Department of Physiology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
authors.forename: Miika
authors.initials: M
authors.lastname: Koskinen
authors.affiliation: Systems and Clinical Neuroscience, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Yevhen
authors.initials: Y
authors.lastname: Hlushchuk
authors.affiliation: Systems and Clinical Neuroscience, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Department of Neurology, Helsinki University Hospital, and Clinical Neurosciences, Neurology, University of Helsinki, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Forss
authors.affiliation: Systems and Clinical Neuroscience, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Department of Art, Aalto University School of Arts, Design and Architecture, Helsinki, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Hari
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001931:Brain Mapping; D020918:Complex Regional Pain Syndromes / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000503:physiopathology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010147:Pain Measurement; D010775:Photic Stimulation; D018709:Statistics, Nonparametric
chemical_list: D010100:Oxygen
keywords: Action observation; CRPS; chronic pain; fMRI; multivoxel pattern analysis