The Mechanism Of Impaired Response Inhibition On High Impulsivity In Borderline Personality Disorder

Aim: Impulsivity is one of the core symptoms of borderline personality disorder(BPD),and one of the mechanisms of high impulsivity of BPD might be impaired response inhibition.This study was aimed to investigate the pattern and clarify the neuroelectrophysiological mechanism of impulsivity among patients with BPD using self-reported,behavioral and electroencephalographic(EEG)measurements.Method: A total of 30 patients diagnosed with BPD and 47 healthy controls matched on gender,age and intelligence were enrolled in the study.Borderline Symptom List(BSL-23),Center for Epidemiologic Studies Depression Scale(CES-D),State Anxiety Inventory(SAI),Barratt Impulsiveness Scale(BIS-11),and Difficulties in Emotion Regulation Questionnaire(DERS)were adopted to evaluate subject’s borderline symptom severity,depression,anxiety,trait impulsivity,and use of emotion regulation strategies,respectively.Two affective Go-Nogo tasks were adopted to measure subject’s ability of response inhibition.Behavioral and EEG data were collected simultaneously,after which the amplitudes and latencies of N2 and P3,two components of event-related potentials,and the difference waves between different conditions and responses were extracted,calculated,and analyzed.Phase-locking Value(PLV)was adopted to quantify the functional connectivity in the time windows and frequency bands of interests.Chi-square test and independent t-test were applied to examine the between-group differences in demographic and psychometric data;repeated-measure ANOVA was applied to compare the across-subject and within-subject differences in behavioral performance and the ERP components of interest.Independent t-test and NBS correction were adopted to examine the differences in functional connectivity between groups.Results:(1)Compared with HC,BPD showed high trait impulsivity.(2)BPD showed significantly longer Neutral-Go Reaction Time than HC.(3)BPD showed marginally larger Negative Nogo-Neutral Nogo Nd2 amplitude than HC.A significant Group×Side interaction existed for Negative Nogo-Negative Go Nd2 amplitude.BPD also showed significantly smaller Negative Go-Neutral Go Pd3 amplitude than HC.(4)In BPD group,BIS score was positively correlated with the scores of DERS and its two subscales,and negatively with F5 Negative Nogo N2 latency,and P3 and P6 Negative Nogo-Neutral Nogo Pd3 latency.(5)Compared with HC,for Negative-Nogo,in P3 window,BPD showed reduced connectivity in frontal areas(p=0.0496)in alpha band,and reduced frontalparietal connectivity in beta band(p=0.002).For Neutral-Go,in N2 window,BPD showed reduced parietal connectivity in beta band(p=0.036).For Neutral-Nogo,in N2 window,BPD showed elevated frontal connectivity in gamma band(p=0.005)and reduced parietal(p<0.001)and temporal(p=0.007)connectivity,and in P3 window,reduced parietal/temporal connectivity in gamma band(p=0.015).For Negative-Go,in P3 window,BPD showed elevated frontal-parietal connectivity in alpha band(p=0.033)and reduced frontal-parietal/temporal connectivity in gamma band(p=0.002).Conclusion: The impulsivity of BPD is associated with its emotion dysregulation and electrophysiological pattern of deficiency in response inhibition.Abnormalities in difference waves related to emotional stimuli and frontal and parietal functional connectivities might be the electrophysiological patterns of borderline personality disorder.Deficiencies in frontal-parietal connectivity might underlie the neural mechanism of impulsivity in borderline personality disorder.