Neural abnormalities in cognitive subprocesses of emotional conflict control in bipolar II disorder: Evidence from ERPs and brain functional networks.

Patients with bipolar disorder (BD) exhibit deficits in emotional conflict control. These abnormalities may be related to alterations in distinct cognitive subprocesses involved in emotional conflict processing; however, the specific stages affected remain unclear. Given the temporal and stage-dependent nature of emotional conflict control, examining specific processing stages may clarify the mechanisms underlying these deficits in BD. Therefore, this study combined a face-word emotional Stroop task with EEG, integrating event-related potentials (ERPs) and brain functional network analyses to characterize the cognitive subprocesses involved in emotional conflict control in bipolar II disorder (BD-II). BD-II patients showed significant abnormalities in early cognitive stages, including emotional stimulus perception and conflict monitoring (p < 0.05). These abnormalities were mainly reflected by reduced N200 amplitudes, right temporal region (T8)-centered network changes, and alterations in both global topology and frontal network organization. Machine learning analysis further suggested that these abnormal electrophysiological features may contain information relevant to distinguishing BD-II patients from healthy controls (HC), yielding an accuracy of 83.3% on the held-out test set. In summary, this study suggests that emotional conflict control deficits in BD-II are mainly reflected in early-stage electrophysiological abnormalities, with ERP amplitude changes and T8-centered right temporal network alterations representing the core findings. These findings provide candidate EEG features for further investigation of emotional conflict control abnormalities in BD-II, but require validation in larger independent samples.