I think their theories are pretty much all ass-backwards:
CPET and heart rate monitors are a good indication that it's not just amplified signals. We can (and often do) push through the pain, but then crash. I've had a major leg muscle stop working entirely. And I consistently have elevated blood lactate levels many hours after mild exertion. All of that suggests to me that I'm not amplifying signals from normal levels of metabolities - my metabolities (and muscles) are the subject of some sort of malfunction.
Or a numbing agent simply blocks local pain like it's supposed to?
Or processing is normal, and there's actually something peripheral causing more pain. If it were central, the signals would be consistently amplified, not fluctuating.
Glad it's not just me Val. I haven't read the study - maybe it would change my mind - but from reading the press release quotes from the study authors the idea that it is due to the signals being amplified seems unlikely to me, it annoys me when I read unreasonable conclusions not backed up by the findings, and especially when it is unnecessarily complex and more obvious explanations are rejected/or not talked about. The author's conclusions are just not in keeping with my experience and knowledge of the disease. I can't see any reason to reach this conclusion from the study. Perhaps the authors reached this conclusion because of their possible route to where they are now:
The idea that ME pain is all in the head has been around for ages. It's also an idea put forward for lots of other pain conditions that science has yet to figure out. It looks like these researchers do not believe that idea in ME (a good thing). And so they appear to have set out to test if it is peripheral pain or in the mind and the study idea does that quite well, I think. But having done that they then reach a conclusion that seems closer to the original idea they try to disprove than more likely explanations.
My conclusion would be that the pain is real and correct; there is something causing that pain locally, not that the pain receptors or whatever are amplifying normal signals.
ME causes lots of problems all over the body, immunological etc. And as you point out Val, CPET, heart rate, etc. Lots of things actually. It's not just a pain condition. Some patients don't even get pain but still clearly have ME. The conclusion that normal signals are amplified doesn't explain all the other stuff going on, it doesn't really fit.