These symptoms indicate abnormalities in brain function, and Kiran Thapaliya, Leighton Barnden, Sonya Marshall-Gradisnik and colleagues have been investigating the root of these abnormalities in a series of experiments, funded by ME Research UK, involving imaging of the brain.

Their findings in ME/CFS to date include brainstem volume changes (which correlated with measures of pain and breathing difficulty), impaired functional connectivity between specific brain regions, and raised brain neurochemical levels.

Another, earlier study also found differences in the hippocampus in people with ME/CFS. The hippocampus is a brain structure involved in memory and learning, and is comprised of different areas, or subfields, which each have specific jobs.

The cognitive problems associated with ME/CFS are largely shared by individuals with long COVID, so it makes sense to look for these changes in long COVID also, and to compare the two illnesses.