Evidence coming from neuropsychological studies has showed the presence of cognitive alterations in fibromyalgia. Such dysfunctions are especially remarkable when the set in motion of executive control processes, such as inhibition, is required to perform successfully; however, neural data related to these mechanisms are very scarce. Present study tried to characterize cognitive inhibition mechanisms, as part of the attentional control functions, in patients with fibromyalgia. Participants (two groups: fibromyalgia patients and healthy control participants) were asked to perform in an emotional Stroop task while event-related potentials (ERP) were recorded. Four different emotional interference conditions were created: fibromyalgia symptom-related words, arousing-negative, arousing-positive and neutral words. Brain activity and behavioral data were analyzed. Principal component analyses were employed to reliably define ERP components along with a source-estimation technique. Symptom-related words elicited greater frontal P450 amplitudes and enhanced activation within right inferior frontal gyrus as compared to the rest of stimuli. This effect was only true for the fibromyalgia group. Behavioral contrasts, however, did not produce significant differences. Scalp and source estimation findings suggest the presence of a specific difficulty in cognitive inhibition in fibromyalgia patients (under conditions intimately linked with the core concerns of their disease). Data point to the involvement of right inferior frontal cortices in this inefficient mechanism, which might cause an enhanced and dysfunctional effort of processing to achieve only a comparable performance to healthy people. Implications of these results are discussed. Nevertheless, further investigations are needed to better understand dysfunctional cognition in fibromyalgia.
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