BackgroundGulf War Illness (GWI) affects 30% of veterans from the 1991 Gulf War and has no known cause. Everyday symptoms include pain, fatigue, migraines, and dyscognition. A striking syndromic feature is post-exertional malaise (PEM). This is recognized as an exacerbation of everyday symptoms following a physically stressful or cognitively demanding activity. The underlying mechanism of PEM is unknown. We previously reported a novel paradigm that possibly captured evidence of PEM by utilizing fMRI scans taken before and after sub-maximal exercises. We hypothesized that A) exercise would be a sufficient physically stressful activity to induce PEM and B) Comparison of brain activity before and after exercise would provide evidence of PEM’s effect on cognition. We reported two-exercise induced GWI phenotypes with distinct changes in brain activation patterns during the completion of a 2-back working memory task (also known as two-back > zero-back).ResultsHere we report unanticipated findings from the reverse contrast (zero-back > two-back), which allowed for the identification of task-related deactivation patterns. Following exercise, patients developed a significant increase in deactivation patterns within the Default Mode Network (DMN) that was not seen in controls. The DMN is comprised of regions that are consistently down regulated during external goal-directed activities and is often altered within many neurological disease states.ConclusionsExercise-induced alterations within the DMN provides novel evidence of GWI pathophysiology. More broadly, results suggest that task-related deactivation patterns may have biomarker potential in Gulf War Illness.

中文翻译：

---

演习挑战改变了海湾战争疾病中的默认模式网络动态

背景海湾战争病 (GWI) 影响了 1991 年海湾战争中 30% 的退伍军人，并且原因不明。日常症状包括疼痛、疲劳、偏头痛和认知障碍。一个显着的综合征特征是劳累后不适（PEM）。这被认为是身体压力或认知要求高的活动后日常症状的恶化。PEM 的潜在机制尚不清楚。我们之前报道了一种新范式，该范式可能通过利用次最大运动前后进行的 fMRI 扫描来捕获 PEM 的证据。我们假设 A) 运动是一种足以诱发 PEM 的身体压力活动，B) 运动前后大脑活动的比较将提供 PEM 对认知影响的证据。我们报告了两次运动诱导的 GWI 表型，在完成 2-back 工作记忆任务（也称为 2-back > zero-back）期间大脑激活模式发生了明显变化。 -back > two-back），它允许识别与任务相关的停用模式。运动后，患者在默认模式网络 (DMN) 内的失活模式显着增加，这在对照组中没有出现。DMN 由在外部目标导向活动期间持续下调的区域组成，并且在许多神经系统疾病状态中经常发生改变。结论 DMN 内运动引起的改变提供了 GWI 病理生理学的新证据。更广泛地，