Relationships of Affect and Neuroinflammation With Clinical Pain in Veterans With Fibromyalgia

Inclusion Criteria: Inclusion Criteria for Veterans living with FM: * Inclusion Criteria (FM) Age 19 years or older * Widespread pain index (WPI) 7 and symptom severity scale (SSS) score 5 OR WPI 4-6 and SSS score 9 * Generalized pain, defined as pain in at least 4 of 5 regions, is present * Symptoms have been present at a similar level for at least 3 months * A diagnosis of FM is valid irrespective of other diagnoses. A diagnosis of FM does not exclude the presence of other clinically important illnesses * PTSD Checklist-Stressor-Specific Version 1 re-experiencing (intrusion) symptom, 3 avoidance (numbing) symptoms, and 2 hyperarousal symptoms, each present at the level of moderate or higher during the past month, and if the total severity score is 50 or higher Inclusion Criteria for Veterans living without FM: * Age-matched to participant with FM Exclusion Criteria: Exclusion Criteria for Veterans living with FM: * Neurological disorder * Body mass index \> 40 * Chronic kidney disease * Severe cardiac condition (chronic heart failure, stenosis, history of cardiac arrest, defibrillator, angina) * Ischemic heart disease * 90 days of daily opioid use * Beta-blocker * Inability to consent for study participation (9) Significant cognitive impairment, defined as a known diagnosis of dementia (10) MRI contraindications (11) Pregnancy Exclusion Criteria for Veterans living without FM: * Active use of medications affecting pain responses * Neurological disorder * Body mass index \> 40 * MRI contraindications * Pregnancy