Introduction: ‘Conflict’ arises when incompatible response tendencies compete. Prior work has established roles for the anterior cingulate cortex (ACC) and prefrontal cortex (PFC) in detecting and resolving conflict, respectively. Recent functional imaging studies have also posited a separate pathway involving the amygdala for processing conflict with emotional content, but an electrophysiologic account is lacking.
Methods: Human subjects (n=8) who underwent stereotactic depth electrode insertion for epilepsy performed a standard and an emotional conflict task as we recorded local field potentials (LFPs) in the ACC, PFC, and amygdala. The tasks permitted the dissociation of neural selectivity for (1) conflict, (2) level of cognitive control, and (3) emotional valence.
Results: Subjects performed the standard and emotional conflict tasks accurately (98% vs 97% correct) and demonstrated expected conflict-induced response slowing (p<1x10-20 for each). LFPs across the three recording sites indicated robust task-related activity.
In the standard task, most ACC and DLPFC sites were sensitive to both conflict and cognitive control (ACC: 72% vs 51%, DLPFC: 66% vs 59%), with ACC selectivity arising preferentially in the left hemisphere (p=0.007). LFPs in the amygdala also registered both conflict and cognitive control (42% vs 46% of sites).
In the emotional conflict task, the ACC and DLPFC again signaled conflict and cognitive control (ACC: 50% vs 50%, DLPFC: 51% vs 39%). The amygdala was similarly active (41% of sites detecting conflict, 41% indicating level of control, the latter almost exclusively on the left; p=0.001). Of note, the amygdala was more sensitive to emotional valence than either conflict or cognitive control (74% of sites, p=0.02).
Conclusions: Our findings support a distributed network for conflict detection and resolution that is less modular than suggested by existing models. The amygdala indeed registers emotional conflict, but it is at least as sensitive to non-emotional conflict and even more responsive to emotional valence.
Patient Care: Elaborating the processing of conflict may inform rational neurostimulation strategies for treating patients suffering from dysfunction in the affected network (e.g. obsessive-compulsive disorder).
Learning Objectives: By the conclusion of the session, participants should be able to: (1) define cognitive conflict and distinguish between emotional and non-emotional conflict, and (2) outline the circuit for conflict processing.