Neural Mechanisms of Trust and Dyadic Interaction in BPD
Final Report Abstract
In IP3 we examined neural processes associated with immediate social interaction between two persons. For this, we applied a neuroimaging technique that allows for the simultaneous recording of brain signals from two individuals while they engage in immediate social contact and complete interactive tasks, i.e. fMRI-hyperscanning. The aim of the project was the detection of neural aberrances in Borderline Personality Disorder (BPD) that may underlie their everyday difficulties in building and maintaining social relationships. In a first step, we developed a generalizable analysis routine for hyperscanning data based on two independent samples of healthy controls and a basic cooperation task. To account for two-brain fMRI-data, we combined largely data‐driven methods containing minimal a‐priori assumptions. We then identified a novel signature of neural interactive coupling, i.e., a synchronization of a social brain network between partners, which evolved around the right temporoparietal junction (rTPJ). This information flow between the sender’s and receiver’s brain systems was temporally and spatially highly specific to true, immediate interaction, and related to the subjects’ social expertise in everyday life. While speculative, this measure may associate to successful social contact. Subsequently, the approach was applied to BPD. We examined subject pairs each including a healthy subject and either a patient currently diagnosed with BPD, a patient in remission, or a second healthy subject. Strikingly, neural coupling was diminished when the subject pair included a current BPD patient, and group means leveled similar to permutated (non-interacting) pairs. Following the conclusions on healthy subjects, the observation of diminished neural coupling in current BPD may represent the biological mechanism corresponding to difficulties in daily interactions of patients. Contrary to our hypothesis, we found neural coupling restored under remission from BPD. Group comparisons showed no differences to healthy pairs, but higher group means compared to pairs involving patients with a current diagnosis. This indicates (1) that the neurobiology does reflect the observed disorder state, and (2) that the “state” is not irrevocable as previously assumed. These results challenge the current classification of Borderline diagnosis as personality disorder which are by definition largely stable across the lifespan. We find restored neurobiology to accompany remission, suggesting a requirement to adjust diagnosis definition. Neural coupling in patients was furthermore associated with a widely used measure of risk for the disorder, suggesting neural coupling deficits as an additional neural mechanism through which early trauma may translate to impairments in social function. In an economic exchange task, where partners decisions depend on trust in each other and the building of a relationship, we observed a similar link between partners’ rTPJ networks in addition to associations between the cognitive mentalizing regions in the medial prefrontal cortex, associated with evaluating intentions of others. This link was present between healthy partners and remitted patients, but significantly reduced when a current BPD patient was involved. Here, brain networks engaged a differing pattern of brain regions, specifically the reward encoding ventral striatum. Furthermore, the association between brain systems increased over time, related to increasing trustworthy behavior and successful cooperation between partners. All the reported associations between brains were specific to true, immediate contact only and were unique for truly communicating partners, thus showing the importance of the immediate communication in neuroscience studies. The aberrations found for current, but not remitted BPD should be taken into consideration for the classification of BPD as a personality disorder.
Publications
- (2015). Information flow between interacting human brains: Identification, validation, and relationship to social expertise. Proceedings of the National Academy of Sciences, 112(16), 5207-5212
Bilek, E., Ruf, M., Schäfer, A., Akdeniz, C., Calhoun, V. D., Schmahl, C., . . . Meyer-Lindenberg, A.
(See online at https://doi.org/10.1073/pnas.1421831112) - (2017). State-dependent cross-brain information flow in borderline personality disorder. JAMA Psychiatry, 74(9), 949-957
Bilek, E., Stößel, G., Schäfer, A., Clement, L., Ruf, M., Robnik, L., . . . Meyer-Lindenberg, A.
(See online at https://doi.org/10.1001/jamapsychiatry.2017.1682)
