title: Pain anticipatory phenomena in patients with central poststroke pain: a magnetoencephalography study.
abstract: Central poststroke pain (CPSP) is characterized by hemianesthesia associated with unrelenting chronic pain. The final pain experience stems from interactions between sensory, affective, and cognitive components of chronic pain. Hence, managing CPSP will require integrated approaches aimed not only at the sensory but also the affective-cognitive spheres. A better understanding of the brain's processing of pain anticipation is critical for the development of novel therapeutic approaches that target affective-cognitive networks and alleviate pain-related disability. We used magnetoencephalography (MEG) to characterize the neural substrates of pain anticipation in patients suffering from intractable CPSP. Simple visual cues evoked anticipation while patients awaited impending painful (PS), nonpainful (NPS), or no stimulus (NOS) to their nonaffected and affected extremities. MEG responses were studied at gradiometer level using event-related fields analysis and time-frequency oscillatory analysis upon source localization. On the nonaffected side, significantly greater responses were recorded during PS. PS (vs. NPS and NOS) exhibited significant parietal and frontal cortical activations in the beta and gamma bands, respectively, whereas NPS (vs. NOS) displayed greater activation in the orbitofrontal cortex. On the affected extremity, PS (vs. NPS) did not show significantly greater responses. These data suggest that anticipatory phenomena can modulate neural activity when painful stimuli are applied to the nonaffected extremity but not the affected extremity in CPSP patients. This dichotomy may stem from the chronic effects of pain on neural networks leading to habituation or saturation. Future clinically effective therapies will likely be associated with partial normalization of the neurophysiological correlates of pain anticipation.
authors.affiliation: Center for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Raghavan
authors.initials: R
authors.lastname: Gopalakrishnan
authors.affiliation: Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Richard C
authors.initials: RC
authors.lastname: Burgess
authors.affiliation: Center for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, Ohio; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio; and.
authors.forename: Scott F
authors.initials: SF
authors.lastname: Lempka
authors.affiliation: Center for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, Ohio; Department of Neuroscience, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.
authors.forename: John T
authors.initials: JT
authors.lastname: Gale
authors.affiliation: Center for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, Ohio;
authors.forename: Darlene P
authors.initials: DP
authors.lastname: Floden
authors.affiliation: Center for Neurological Restoration, Neurological Institute, Cleveland Clinic, Cleveland, Ohio; Department of Neuroscience, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio machada@ccf.org.
authors.forename: Andre G
authors.initials: AG
authors.lastname: Machado
mesh_terms: D000328:Adult; D059031:Anticipation, Psychological / Q000502:physiology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D059350:Chronic Pain / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D003463:Cues; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D058748:Pain Perception / Q000502:physiology*; D010812:Physical Stimulation; D020521:Stroke / Q000150:complications / Q000503:physiopathology*; D014796:Visual Perception / Q000502:physiology
keywords: central poststroke pain; deep brain stimulation; magnetoencephalography; pain anticipation; thalamic pain syndrome