Aberrant recruitment of the striatum and insula is associated with recalling and suppressing fatigue- and anger-related memories in people with chronic fatigue syndrome/myalgic encephalomyelitis

Research suggests that people with chronic fatigue syndrome tend to suppress emotions more than healthy individuals. However, whether there are also changes in the neural substrates of emotional regulation in people with chronic fatigue syndrome remain unexplored. Specifically, it is unclear whether there is a neural delineation in how fatigue and anger-related memories are recalled or supressed in people with chronic fatigue syndrome. This study investigated this hypothesis using functional magnetic resonance imaging. We compared blood oxygen level-dependent signal changes between people with chronic fatigue syndrome (N=20) and matched controls (N= 20) during a novel task that involved the recall or suppression of fatigue (or anger-related memories). Results revealed a dissociation in the contribution of striatal subregions and the insula when recalling and suppressing anger and fatigue-related memories according to diagnostic status. Principally, patients showed higher blood oxygen level-dependent signal in the left and right rostral caudate during the suppression of fatigue and anger-related memories, respectively. Different patterns were also observed in the way each group recruited the posterior putamen when recalling (or suppressing) anger or fatigue-related memories. In contrast to its prominent suppression in striatal regions, blood oxygen level-dependent signal in the insula was increased in the patient group during the active recall of anger or fatigue-related memories. Cumulatively, these results reveal that chronic fatigue syndrome is associated with demonstrable, physiological changes in the way emotional information is processed and implicate the rostral caudate and insula as targets for further investigation.