Emotion processing and regulation: an electrophysiological investigation among high borderline personality trait individuals

Emotion processing and regulation are fundamental for stable mental functioning and healthy interpersonal relationships. Borderline personality disorder (BPD) is a severe mental disorder where emotional dysregulation is a core feature, yet the neural processes underlying this dysfunction remain poorly understood. We examined bottom-up and top-down mechanisms involved in emotion processing among females selected for high and low levels of BPD traits (HBT and LBT groups). Study 1 (30 participants) employed a modified eStroop paradigm to investigate group differences in event-related potential (ERP) components associated with the implicit (Overt) versus explicit (Covert) processing of prototypical expressions of facial affect (Angry, Fearful, Sad, Happy, and Neutral). Study 2 (32 participants) employed a cognitive modulation paradigm to examine ERPs associated with Reducing one’s emotional response to unpleasant high arousal (HA) and low arousal (LA) images versus Allowing one’s emotional responses to occur. Results from both studies supported the prediction that ERP components would be differently modulated as a function of group status and task. In Study 1, the HBT group showed enhanced Early Anterior Positivity (EAP) modulations to Angry facial expressions relative to Fearful ones when these were not the focus of attention, whereas the LBT group showed enhanced EAP modulations when facial expressions were the focus of attention. This finding suggests hypervigilance to social threat among HBT individuals, with early modulations over the frontal scalp observed as early as 150 ms post-stimulus. In Study 2, the HBT group showed heightened sensitivity to HA images, with dampened responses to LA images observed for the occipital P1 and the frontal EAP. Additionally, they demonstrated difficulties in down-regulating the impact of LA images as measured by enhanced LPP amplitudes over the posterior scalp. Both experiments provide support for a model of abnormal functioning of a neural network sensitive to personally threatening information in BPD and offer evidence for altered processing within early, possibly pre-attentive stages of information processing over the anterior scalp. These findings provide important clues for the understanding of neural mechanisms underlying emotion dysregulation difficulties in BPD.