Examinando por Autor "Wasan, Ajay D."

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    Fibromyalgia is characterized by altered frontal and cerebellar structural covariance brain networks
    (2015-03-04) Kim, Hyungjun; Kim, Jieun; Loggia, Marco L.; Cahalan, Christine M.; García, Ronald G.; Vangel, Mark G.; Wasan, Ajay D.; Edwards, Robert R.; Napadow, Vitaly
    Altered brain morphometry has been widely acknowledged in chronic pain, and recent studies have implicated altered network dynamics, as opposed to properties of individual brain regions, in supporting persistent pain. Structural covariance analysis determines the inter-regional association in morphological metrics, such as gray matter volume, and such structural associations may be altered in chronic pain. In this study, voxel-based morphometry structural covariance networks were compared between fibromyalgia patients (N=42) and age- and sex-matched pain-free adults (N=63).We investigated network topology using spectral partitioning,which can delineate local network submodules with consistent structural covariance. We also explored white matter connectivity between regions comprising these submodules and evaluated the association between probabilistic white matter tractography and pain-relevant clinical metrics. Our structural covariance network analysis noted more connections within the cerebellum for fibromyalgia patients, and more connections in the frontal lobe for healthy controls. For fibromyalgia patients, spectral partitioning identified a distinct submodule with cerebellar connections to medial prefrontal and temporal and right inferior parietal lobes, whose gray matter volume was associated with the severity of depression in these patients. Volume for a submodule encompassing lateral orbitofrontal, inferior frontal, postcentral, lateral temporal, and insular cortices was correlated with evoked pain sensitivity. Additionally, the number ofwhitematter fibers between specific submodule regionswas also associated with measures of evoked pain sensitivity and clinical pain interference. Hence, altered gray and white matter morphometry in cerebellar and frontal cortical regions may contribute to, or result from, pain-relevant dysfunction in chronic pain patients.
  • Publicación
    Acceso abierto
    The somatosensory link : S1 functional connectivity is altered by sustained pain and associated with clinical/autonomic dysfunction in fibromyalgia
    (2015-05) Kim, Jieun; Loggia, Marco L.; Cahalan, Christine M.; Harris, Richard E.; Beissner, Florian; García, Ronald G.; Kim, Hyungjun; Wasan, Ajay D.; Edwards, Robert R.; Napadow, Vitaly
    Objective—Fibromyalgia (FM) is a chronic functional pain syndrome characterized by widespread pain, significant pain catastrophizing, sympathovagal dysfunction, and amplified temporal summation for evoked pain. While several studies have found altered resting brain connectivity in FM, studies have not specifically probed the somatosensory system, and its role in both somatic and non-somatic FM symptomatology. Our objective was to evaluate resting primary somatosensory cortex (S1) connectivity, and explore how sustained, evoked deep-tissue pain modulates this connectivity.Methods—We acquired fMRI and electrocardiography data from FM patients and healthy controls (HC) during rest (REST) and sustained mechanical pressure pain (PAIN) over the lower leg. Functional connectivity associated with different S1 subregions was calculated, while S1leg (leg representation) connectivity was contrast between REST and PAIN, and correlated with clinically-relevant measures in FM. Results—At REST, FM showed decreased connectivity between multiple ipsilateral and cross-hemispheric S1 subregions, which was correlated with clinical pain severity. PAIN, compared to REST, produced increased S1legconnectivity to bilateral anterior insula in FM, but not in HC. Moreover, in FM, sustained pain-altered S1legconnectivity to anterior insula was correlated with clinical/behavioral pain measures and autonomic responses. Conclusion—Our study demonstrates that both somatic and non-somatic dysfunction in FM, including clinical pain, pain catastrophizing, autonomic dysfunction, and amplified temporal summation, are all closely linked with the degree to which evoked deep-tissue pain alters S1 connectivity to salience/affective pain processing regions. Additionally, diminished connectivity between S1 subregions at REST in FM may result from ongoing widespread clinical pain.
  • Publicación
    Acceso abierto
    The somatosensory link in fibromyalgia
    (2015-05) Kim, Jieun; Loggia, Marco L.; Cahalan, Christine M.; Harris, Richard E.; Beissner, Florian; García, Ronald G.; Kim, Hyungjun; Barbieri, Riccardo; Wasan, Ajay D.; Edwards, Robert R.; Napadow, Vitaly
    Objective.Fibromyalgia (FM) is a chronic func-tional pain syndrome characterized by widespread pain,significant pain catastrophizing, sympathovagal dysfunc-tion, and amplified temporal summation for evoked pain.While several studies have demonstrated altered restingbrain connectivity in FM, studies have not specificallyprobed the somatosensory system and its role in bothsomatic and nonsomatic FM symptoms. Our objective wasto evaluate resting primary somatosensory cortex (S1) con-nectivity and to explore how sustained, evoked deep tissuepain modulates this connectivity.Methods.We acquired functional magnetic reso-nance imaging and electrocardiography data on FMpatients and healthy controls during rest (the rest phase)and during sustained mechanical pressure–induced painover the lower leg (the pain phase). Functional connectiv-ity associated with different S1 subregions was calculated,while S1legconnectivity (representation of the leg in theprimary somatosensory cortex) was contrasted betweenthe rest phase and the pain phase and was correlated withclinically relevant measures in FM.Results.During the rest phase, FM patientsshowed decreased connectivity between multiple ipsilat-eral and cross-hemispheric S1 subregions, which wascorrelated with clinical pain severity. Compared to therest phase, the pain phase produced increased S1legconnectivity to the bilateral anterior insula in FMpatients, but not in healthy controls. Moreover, in FMpatients, sustained pain–altered S1legconnectivity tothe anterior insula was correlated with clinical/behavioral pain measures and autonomic responses.Conclusion.Our study demonstrates that bothsomatic and nonsomatic dysfunction in FM, includingclinical pain, pain catastrophizing, autonomic dysfunction,and amplified temporal summation, are closely linkedwith the degree to which evoked deep tissue pain alters S1 connectivity to salience/affective pain-processing regions. Additionally, diminished connectivity between S1 subregions during the rest phase in FM may result from ongoing widespread clinical pain.