With respect to the reviewer’s comment regarding the lack of EIH in controls, we have included some additional information to demonstrate the consistency of our findings with previous research. The passage now reads: “However, it appears that the exercise bout as prescribed was not a sufficient stimulus to induce a decrease in pain sensitivity in our pain-free controls. This is consistent with previous literature regarding the effects of acute exercise on pain in healthy controls, which typically finds that higher intensity exercise is necessary to elicit a hypoalgesic response [33].” Additionally, we want to again mention that our study was not primarily designed to induce EIH in controls; it was designed to examine brain responses to pain following exercise and thus we wanted to ensure that FM patients could complete the exercise bout. Exploring brain responses associated with EIH in healthy individuals would be an interesting future direction.
Following exercise in FM patients, activity was transiently increased in anterior insula and dorsolateral prefrontal cortex (DLPFC) while activity was transienly decreased following rest.