Training in cognitive reappraisal normalizes whole-brain indices of emotion regulation in borderline personality disorder.

BACKGROUND: Borderline personality disorder is the prototypical disorder of emotion dysregulation. We have previously shown that borderline personality disorder patients are impaired in their capacity to engage cognitive reappraisal, a frequently-employed adaptive emotion regulation strategy. METHODS: Here we report on the efficacy of longitudinal training in cognitive reappraisal to enhance emotion regulation in borderline patients. Specifically, the training targeted psychological distancing, a reappraisal tactic whereby negative stimuli are viewed dispassionately as though experienced by an objective, impartial observer. At each of 5 sessions over 2 weeks, 22 borderline (14 Female) and 22 healthy control (13 Female) participants received training in psychological distancing and then completed a widely-used picture-based reappraisal task. Self-reported negative affect ratings and functional magnetic resonance imaging (fMRI) data were acquired at the first and fifth sessions. In addition to behavioral analyses, we performed whole-brain pattern expression analyses using independently-defined patterns for negative affect and cognitive reappraisal implementation for each session. RESULTS: Borderline patients showed a decrease in negative affect pattern expression following reappraisal training, reflecting a normalization in neural activity. They did not, however, show significant change in behavioral self-reports. CONCLUSIONS: To our knowledge, this study represents the first longitudinal fMRI examination of task-based cognitive reappraisal training. Using a brief, proof-of-concept design, the results suggest a potential role for reappraisal training in the treatment of borderline patients.

Sensitization of the Neural Salience Network to Repeated Emotional Stimuli Following Initial Habituation in Patients With Borderline Personality Disorder.

OBJECTIVE: Borderline personality disorder is the prototypical disorder of emotion reactivity and dysregulation, yet there remains limited understanding of its neurocognitive correlates. Two mechanisms that may underlie anomalous reactivity in response to negative stimuli among patients with borderline personality disorder are impairment in habituation and exaggerated sensitization of activity in the neural salience network, including the amygdala, anterior insula, and dorsal anterior cingulate cortex. The authors aimed to reveal the most plausible mechanism by examining the effect of repeated exposure to emotional images both within and across study sessions. METHOD: A total of 75 participants (patients with borderline personality disorder, N=26; patients with avoidant personality disorder included as a psychopathological control group, N=25; and healthy control subjects, N=24) were included in the study analyses. All participants viewed five presentations of the same set of negative and neutral images at each of two sessions, separated by approximately 3 days, while functional MRI data were acquired. Salience network activity, as measured by blood-oxygen-level-dependent signal in anatomically defined regions of interest across the salience network, was compared across the three groups for each presentation at each of the two study sessions. Self-reported negative affect was measured for each trial. RESULTS: Salience network activity showed a main effect of within-session habituation across all groups and sessions. However, a group-by-session interaction was present, such that only patients with borderline personality disorder showed increased salience network activity in response to the images reencountered at the second session, and this increased salience network sensitization predicted greater sensitization in self-reported negative affect. CONCLUSIONS: These results elucidate the neural mechanisms by which patients with borderline personality disorder appraise negative social situations as exaggeratedly salient and suggest potential neurocognitive intervention targets.

Genetic basis for nitrate resistance in Desulfovibrio strains.

Nitrate is an inhibitor of sulfate-reducing bacteria (SRB). In petroleum production sites, amendments of nitrate and nitrite are used to prevent SRB production of sulfide that causes souring of oil wells. A better understanding of nitrate stress responses in the model SRB, Desulfovibrio vulgaris Hildenborough and Desulfovibrio alaskensis G20, will strengthen predictions of environmental outcomes of nitrate application. Nitrate inhibition of SRB has historically been considered to result from the generation of small amounts of nitrite, to which SRB are quite sensitive. Here we explored the possibility that nitrate might inhibit SRB by a mechanism other than through nitrite inhibition. We found that nitrate-stressed D. vulgaris cultures grown in lactate-sulfate conditions eventually grew in the presence of high concentrations of nitrate, and their resistance continued through several subcultures. Nitrate consumption was not detected over the course of the experiment, suggesting adaptation to nitrate. With high-throughput genetic approaches employing TnLE-seq for D. vulgaris and a pooled mutant library of D. alaskensis, we determined the fitness of many transposon mutants of both organisms in nitrate stress conditions. We found that several mutants, including homologs present in both strains, had a greatly increased ability to grow in the presence of nitrate but not nitrite. The mutated genes conferring nitrate resistance included the gene encoding the putative Rex transcriptional regulator (DVU0916/Dde_2702), as well as a cluster of genes (DVU0251-DVU0245/Dde_0597-Dde_0605) that is poorly annotated. Follow-up studies with individual D. vulgaris transposon and deletion mutants confirmed high-throughput results. We conclude that, in D. vulgaris and D. alaskensis, nitrate resistance in wild-type cultures is likely conferred by spontaneous mutations. Furthermore, the mechanisms that confer nitrate resistance may be different from those that confer nitrite resistance.

Rapid transposon liquid enrichment sequencing (TnLE-seq) for gene fitness evaluation in underdeveloped bacterial systems.

Whole-genome fitness analysis in microbes that uses saturating transposon mutagenesis combined with massively parallel sequencing (Tn-seq) is providing a measure of the contribution of each gene to a given growth condition. With this technique, gene fitness profiles and essential genes are discovered by simultaneous analyses of whether the absence of each gene product alters the growth kinetics of the bacterium. Here we modify the standard Tn-seq procedure to simplify and shorten the process by including delivery of the transposon through conjugation and liquid culture enrichment of the mutant pool, creating transposon liquid enrichment sequencing (TnLE-seq). To illustrate the success of these modifications and the robustness of the procedure, analyses of gene fitness of two cultures of the strictly anaerobic bacterium Desulfovibrio vulgaris Hildenborough were performed, with growth on lactate as the electron donor and sulfate as the electron acceptor. These data demonstrate reproducibility and provide a base condition for analysis of fitness changes in deletion mutants and in various growth conditions. The procedural modifications will facilitate the application of this powerful genetic analysis to microbes lacking a facile genetic system. Pilot studies produced 2.5×10(5) and 3.4×10(5) unique insertion mutants in the anaerobe Desulfovibrio vulgaris Hildenborough grown under typical laboratory conditions in rich medium. These analyses provided two similar high-resolution maps of gene fitness across the genome, and the method was also applied to growth in minimal medium. These results were also compared to the coverage obtained with a ca. 13,000-member cataloged transposon library constructed by sequencing transposon insertion sites in individual mutants.