Great work here by Jared Younger and his team. He is rapidly ascending the ranks and he might be at this moment the researcher with the best flow of findings.
If I could summarise this paper I'd say they went looking for chemicals in the brain that might be evidence of neuroinflammation. They found plenty. They were able to specify the locations of various of these chemicals in different brain regions.
Looks like Choline was the most prominent, in the left anterior cingulate region.
The most significant difference in the study was CHO in the left ACC. We note this area in particular because it is the only region to survive corrections for multiple comparisons, and because it has been noted as a critically important region mediating cytokine-induced fatigue and mood deterioration (Capuron et al. 2005; Harrison et al. 2009). Cytokineinduced fatigue and depressive symptoms have previously been attributed to inflammation in the ACC, as indicated by elevated glutamate on MRS (Haroon et al. 2014). The current study provides further evidence for the link between ACC inflammation and fatigue by demonstrating that ME/CFS patients show elevated CHO in this region.
The wikipedia on this part of the brain mentions autonomic functions which got me excited but mostly focuses on error detection and morality. It's hard to say if those are just things psychologists like to test or if those are really the core functions of this part of the brain. I don't feel we are especially morally deficient! Probably neuroscience is not yet really advanced enough to find regions of the brain that have very specific functions.
It's worth mentioning that in this study the observations are "normalised" by comparing to creatine levels. This looks to be standard practice but I can see an argument that creatine - an amino acid - could vary in patients. I hope Younger has a plan to rule out that as a potential source of bias.