Effective mental functioning requires that cognition be protected from emotional conflict due to interference by task-irrelevant emotionally salient stimuli. The neural mechanisms by which the brain detects and resolves emotional conflict are still largely unknown, however. Drawing on the classic Stroop conflict task, we developed a protocol that allowed us to dissociate the generation and monitoring of emotional conflict from its resolution. Using functional magnetic resonance imaging (fMRI), we find that activity in the amygdala and dorsomedial and dorsolateral prefrontal cortices reflects the amount of emotional conflict. By contrast, the resolution of emotional conflict is associated with activation of the rostral anterior cingulate cortex. Activation of the rostral cingulate is predicted by the amount of previous-trial conflict-related neural activity and is accompanied by a simultaneous and correlated reduction of amygdalar activity. These data suggest that emotional conflict is resolved through top-down inhibition of amygdalar activity by the rostral cingulate cortex.

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Summary:Purpose: The right (nondominant) amygdala is crucial for processing facial emotion recognition (FER). Patients with temporal lobe epilepsy (TLE) associated with mesial temporal sclerosis (MTS) often incur right amygdalar damage, resulting in impaired FER if TLE onset occurred before age 6 years. Consequently, early right mesiotemporal insult has been hypothesized to impair plasticity, resulting in FER deficits, whereas damage after age 5 years results in no deficit. The authors performed this study to test this hypothesis in a uniformly seizurefree postsurgical population.Methods: Controls (n = 10), early-onset patients (n = 7), and late-onset patients (n = 5) were recruited. All patients had nondominant anteromedial temporal lobectomy (AMTL), Wadaconfirmed left-hemisphere language dominance and memory support, MTS on both preoperative MRI and biopsy, and were Engel class I 5 years postoperatively. By using a standardized (Ekman and Friesen) human face series, subjects were asked to match the affect of one of two faces to that of a simultaneously presented target face. Target faces expressed fear, anger, or happiness.Results: Statistical analysis revealed that the early-onset group had significantly impaired FER (measured by percentage of faces correct) for fear (p = 0.036), whereas the FER of the late-onset group for fear was comparable to that of controls. FER for anger and happiness was comparable across all three groups.Conclusions: Despite seizure control/freedom after AMTL, early TLE onset continues to impair FER for frightened expressions (but not for angry or happy expression), whereas late TLE onset does not impair FER, with no indication that AMTL resulted in FER impairment. These results indicate that proper development of the right amygdala is necessary for optimal fear recognition, with other neural processes unable to compensate for early amygdalar damage. Key Words: EpilepsyFacial emotion recognition-Curative anteromedial temporal lobectomy-Nondominant amygdala-Mesial temporal sclerosis.Human facial expressions convey important emotional information, such that the mere observation of an angry or fearful face can elicit strong visceral responses, such as sweating and increased heart rate (1,2). Both lesion and neuroimaging studies have demonstrated that the amygdala plays a large role in processing and mediating autonomic and behavioral responses to emotionally relevant stimuli and participates in facial-expression processing and emotion recognition of visual stimuli (3-11). Additional evidence suggests that bilateral (but not unilateral) amygdala damage results in generalized facial emotion recognition (FER) failure, with fear being most severely affected (3,5,12,13).

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