Repositorio Digital

Resumen en ingles

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.