Individuals with borderline personality disorder (BPD) commonly display deficits in emotion regulation, but findings in the area of social cognitive (e.g., theory of mind, ToM) capacities have been heterogeneous. The aims of the current study were to investigate differences between patients with BPD and controls in functional connectivity (1) between the emotion and ToM network and (2) in the default mode network (DMN). Functional magnetic resonance imaging was used to investigate 19 healthy controls and 17 patients with BPD at rest and during ToM processing. Functional coupling was analysed. Significantly decreased functional connectivity was found for patients compared with controls between anterior cingulate cortex and three brain areas involved in ToM processes: the left superior temporal lobe, right supramarginal/inferior parietal lobes, and right middle cingulate cortex. Increased functional connectivity was found in patients compared with controls between the precuneus as the DMN seed and the left inferior frontal lobe, left precentral/middle frontal, and left middle occipital/superior parietal lobes during rest. Reduced functional coupling between the emotional and the ToM network during ToM processing is in line with emotion-regulation dysfunctions in BPD. The increased connectivity between precuneus and frontal regions during rest might be related to extensive processing of internal thoughts and self-referential information in BPD.
Current theories of borderline personality disorder (BPD) propose that the experience of early life trauma (e.g., childhood abuse or maternal separation), genetics, neurobiological alterations, or a combination of the above may play crucial roles in the development of the disorder (Goodman et al., 2004 and Steele and Siever, 2010). In recent years, the spotlight has increasingly been focused on neurobiological abnormalities revealed using in vivo neuroimaging techniques. This focus has resulted in a growing body of evidence supporting the existence of functional neurobiological disturbances in BPD (Goodman et al., 2004 and Foti et al., 2011). The majority of previous functional magnetic resonance imaging (fMRI) studies in BPD have looked at activation abnormalities in regions understood to be involved in the regulation of stress responses, emotion and affect, amongst others. The most common finding amongst these studies is that of hyperactivity in the amygdala and insula of BPD patients as well as decreased frontal activity, e.g., in the anterior cingulate cortex (ACC), compared with controls during tasks that involve the processing of emotionally aversive stimuli (Donegan et al., 2003, Minzenberg et al., 2007, O’Neill and Frodl, 2012 and Krause-Utz et al., 2014).
Social cognitive aspects like mentalization and theory of mind (ToM), although relevant to BPD and its therapy, have thus far only been explored at a rudimentary level in BPD research. ToM describes the ability an individual has to understand and appreciate that others can have mental states (wants, needs, beliefs, knowledge, emotions, etc.) different from one׳s own, and to understand that these can be used to explain and predict the behaviours of others ( Saxe and Kanwisher, 2003). Mentalization is the process by which we implicitly and explicitly interpret the actions of ourselves and others as meaningful on the basis of intentional mental states ( Bateman and Fonagy, 2004), and thus mentalization shares similarities with the concept of ToM. A deficit in this ability is found in a number of psychiatric and neurodevelopmental disorders, BPD being no exception ( Bouchard et al., 2010). Amongst individuals with BPD, researchers have suggested that a deficit in cognitive empathy may contribute to the interpersonal dysfunction typically observed ( Harari et al., 2010). Franzen et al. (2011) used the trust game to analyse processes of mentalising in a simulated social interaction situation. BPD patients adjusted their investment to the fairness of their partner. In contrast, healthy controls disregarded the trustees׳ fairness in the presence of emotional facial expressions. Both groups performed equally in an emotion-recognition task and assessed the trustees׳ fairness comparably ( Franzen et al., 2011). When the unfair trustee provided emotional cues, BPD patients assessed their own behaviour as more fair, while the lack of cues led patients to assess their own behaviour as unfair. The authors thus concluded that BPD patients are superior in the attribution of mental states to interaction partners when emotional cues are present ( Franzen et al., 2011).
