Attentional emotion control in dysphoric and non-dysphoric patients with epilepsy

The high prevalence of depression among epileptic patients has led to the hypothesis that depression and epilepsy may share specific common pathophysiological mechanisms. Both diseases are associated with structural and functional abnormalities in temporal and frontal lobe structures that play an important role in the control and regulation of emotions. Hence, to explore this comorbidity appears valuable in order to gain insight into emotion control brain mechanisms. Maladaptative attentional biases towards negative or threat related cues in the environment are thought to be one of the most important vulnerability factors for depression. Therefore, in this study, we compared attentional control effects towards emotion-laden stimuli for epileptic patients with vs. without (trait-related) dysphoria. Event-related potentials (ERPs) were recorded while patients performed a standard object-based attention task in which fearful, sad or neutral faces were presented either at attended or unattended spatial locations. At the behavioral level, results show slower reaction times when task-relevant faces carried a negative emotional expression, regardless of the level of dysphoria. ERP results show that the emotional content of the face had a significant effect on the amplitude of the vertex positive potential (VPP) and late positive potential (LPP), however, for the dysphoric patients selectively. When faces were task-relevant (attended), these patients had a larger VPP for emotional compared to neutral faces. When faces were task-irrelevant (unattended), results show an enhanced LPP in response to fearful and sad faces, compared to neutral faces, for the dysphoric patients only. By contrast, the VPP and LPP components of non-dysphoric patients did not vary in amplitude with the emotional content of the faces. These results suggest an enhanced attentional bias towards negative emotional stimuli in epileptic patients with dysphoria. Moreover, our new ERP results show that object-based attention towards the emotional content of the faces actually influenced the expression of this bias, changing both face-specific brain mechanisms (VPP) as well as later stages of face stimulus processing (LPP). A better understanding of the possible abnormalities arising during attentional emotion control may prove useful in improving the diagnosis, treatment and prevention of mood disorders in epilepsy