Exercise alters cerebellar and cortical activity related to working memory in phenotypes of Gulf War Illness.

Observed Findings

• GWI-START subgroup showed exercise-induced deactivation of cerebellar dentate nucleus and vermis regions associated with working memory
• GWI-STOPP subgroup demonstrated significant post-exercise activation of anterior supplementary motor area, possibly reflecting altered salience network engagement
• GWI-POTS subgroup showed a trend toward vermis deactivation after exercise
• Controls and all three GWI subgroups showed no differences in brain activity during the working memory task before exercise
• Exercise had no detectable effects on brain activation patterns in healthy control subjects

Inferred Conclusions

• Different autonomic phenotypes of Gulf War Illness exhibit distinct patterns of post-exertional cognitive brain dysfunction, suggesting mechanistic heterogeneity within the condition
• The cerebellum and anterior supplementary motor area appear to play central roles in post-exertional malaise, with specific involvement depending on autonomic subtype
• Autonomic dysfunction (POTS and START) may be mechanistically linked to cerebellar dysfunction through pathways yet to be elucidated
• Post-exertional brain changes occur selectively in Gulf War Illness patients and not in healthy controls, supporting a pathophysiologic basis for post-exertional malaise

Remaining Questions