Subjective and behavioural results. (A) Results of subjective fatigue sensation. Just before (Before) and after (After) the fMRI experiments, subjects were asked to rate subjective sensation of fatigue on the visual analogue scale (VAS) from 0 to 10. (B-DS) Behavioural results. In the pre- (Pre) or post-fatigue (Post) sessions, subjects performed visual search or null trials for 6 min. During these sessions, percentage of the response within 3.5 sec (B), accuracy (C), and reaction time (D) were recorded. Closed columns, normal subjects; open columns, CFS subjects. **P < 0.01, significant difference; ns, no significant difference (paired t-test). Data are mean and SEM.