The dissociative subtype of posttraumatic stress disorder is associated with subcortical white matter network alterations

Posttraumatic stress disorder (PTSD) is characterized by intrusions, avoidance, and hyperarousal while patients of the dissociative subtype (PTSD-D) experience additional dissociative symptoms. A neurobiological model proposes hyper-inhibition of limbic structures mediated by prefrontal cortices to underlie dissociation in PTSD. Here, we tested whether functional alterations in fronto-limbic circuits are underpinned by white matter network abnormalities on a network level. 23 women with PTSD-D and 19 women with classic PTSD participated. We employed deterministic diffusion tractography and graph theoretical analyses. Mean fractional anisotropy (FA) was chosen as a network weight and group differences assessed using network-based statistics. No significant white matter network alterations comprising both frontal and limbic structures in PTSD-D relative to classic PTSD were found. A subsequent whole brain exploratory analysis revealed relative FA alterations in PTSD-D in two subcortical networks, comprising connections between the left amygdala, hippocampus, and thalamus as well as links between the left ventral diencephalon, putamen, and pallidum, respectively. Dissociative symptom severity in the PTSD-D group correlated with FA values within both networks. Our findings suggest fronto-limbic inhibition in PTSD-D may present a dynamic neural process, which is not hard-wired via white matter tracts. Our exploratory results point towards altered fiber tract communication in a limbic-thalamic circuit, which may underlie (a) an initial strong emotional reaction to trauma reminders before conscious regulatory processes are enabled and (b) deficits in early sensory processing. In addition, aberrant structural connectivity in low-level motor regions may present neural correlates for dissociation as a passive threat-response

Neural correlates of acute post-traumatic dissociation:a functional neuroimaging script-driven imagery study

Background: Current neurobiological models of post-traumatic stress disorder (PTSD) assume excessive medial frontal activation and hypoactivation of cortico-limbic regions as neural markers of post-traumatic dissociation. Script-driven imagery is an established experimental paradigm that is used to study acute dissociative reactions during trauma exposure. However, there is a scarcity of experimental research investigating neural markers of dissociation; findings from existing script-driven neuroimaging studies are inconsistent and based on small sample sizes. Aims: The current aim was to identify the neural correlates of acute post-traumatic dissociation by employing the script-driven imagery paradigm in combination with functional magnetic resonance imaging. Method: Functional neuroimaging data was acquired in 51 female patients with PTSD with a history of interpersonal childhood trauma. Blood-oxygen-level-dependent response during the traumatic (versus neutral) autobiographical memory recall was analysed, and the derived activation clusters were correlated with dissociation measures. Results: During trauma recall, enhanced activation in the cerebellum, occipital gyri, supramarginal gyrus and amygdala was identified. None of the derived clusters correlated significantly with dissociative symptoms, although patients reported increased levels of acute dissociation following the paradigm. Conclusions: The present study is one of the largest functional magnetic resonance imaging investigations of dissociative neural biomarkers in patients with PTSD undergoing experimentally induced trauma confrontation to elicit symptom-specific brain reactivity. In light of the current reproducibility crisis prominent in neuroimaging research owing to costly and time-consuming data acquisition, the current (null) findings highlight the difficulty of extracting reliable neurobiological biomarkers for complex subjective experiences such as dissociation

Multiple sequence alignment based on set covers

We introduce a new heuristic for the multiple alignment of a set of sequences. The heuristic is based on a set cover of the residue alphabet of the sequences, and also on the determination of a significant set of blocks comprising subsequences of the sequences to be aligned. These blocks are obtained with the aid of a new data structure, called a suffix-set tree, which is constructed from the input sequences with the guidance of the residue-alphabet set cover and generalizes the well-known suffix tree of the sequence set. We provide performance results on selected BAliBASE amino-acid sequences and compare them with those yielded by some prominent approaches

Classifying national drinking patterns in Europe between 2000 and 2019: A clustering approach using comparable exposure data

Background and aims: Previously identified national drinking patterns in Europe lack comparability and might be no longer be valid due to changes in economic conditions and policy frameworks. We aimed to identify the most recent alcohol drinking patterns in Europe based on comparable alcohol exposure indicators using a data-driven approach, as well as identifying temporal changes and establishing empirical links between these patterns and indicators of alcohol-related harm. Design: Data from the World Health Organization's monitoring system on alcohol exposure indicators were used. Repeated cross-sectional hierarchical cluster analyses were applied. Differences in alcohol-attributable harm between clusters of countries were analyzed via linear regression. Setting: European Union countries, plus Iceland, Norway and Ukraine, for 2000, 2010, 2015 and 2019. Participants/Cases: Observations consisted of annual country data, at four different time points for alcohol exposure. Harm indicators were only included for 2019. Measurements: Alcohol exposure indicators included alcohol per capita consumption (APC), beverage-specific consumption and prevalence of drinking status indicators (lifetime abstainers, current drinkers, former drinkers and heavy episodic drinking). Alcohol-attributable harm was measured using age-standardized alcohol-attributable Disability-Adjusted Life Years (DALYs) lost and deaths per 100 000 people. Findings: The same six clusters were identified in 2019, 2015 and 2010, mainly characterized by type of alcoholic beverage and prevalence drinking status indicators, with geographical interpretation. Two-thirds of the countries remained in the same cluster over time, with one additional cluster identified in 2000, characterized by low APC. The most recent drinking patterns were shown to be significantly associated with alcohol-attributable deaths and DALY rates. Compared with wine-drinking countries, the mortality rate per 100 000 people was significantly higher in Eastern Europe with high spirits and ‘other’ beverage consumption [(Formula presented.) = 90, 95% confidence interval (CI) = 55–126], and in Eastern Europe with high lifetime abstainers and high spirits consumption ((Formula presented.) = 42, 95% CI = 4–78). Conclusions: European drinking patterns appear to be clustered by level of beverage-specific consumption, with heavy episodic drinkers, current drinkers and lifetime abstainers being distinguishing factors between clusters. Despite the overall stability of the clusters over time, some countries shifted between drinking patterns from 2000 to 2019. Overall, patterns of drinking in the European Union seem to be stable and partly determined by geographical proximity. © 2024 World Health Organization; licensed by Society for the Study of Addiction. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.We thank Alexandra Fleischmann, Ilinca Radu, Dag Rekve and Vladimir Poznyak for establishing and maintaining the WHO global monitoring framework for alcohol and health and the regular updates of the Global Information System on Alcohol and Health; the data analyzed as part of this contribution were collected within this monitoring framework. We also like to express our gratitude to all nominated focal points from Member States, who have filled out the surveys and provided the needed data, as well as to Sergei Bychkov and Sumudu Kasturiarachchi for their overall support with the coordination of data collection and validation procedures in the WHO/Europe. The research leading to these results or outcomes has received funding from the EU4Health under contribution agreement no. SANTE/2022/SI2.883729 (Addressing alcohol harm—capacity building, raising awareness and implementation of best practices in the Union). Its contents are the sole responsibility of the authors and do not necessarily reflect the views of the European Commission. J.R. and K.D.S. were in part supported by a contract by the WHO from the WHO/PAHO Collaboration Centre. J.R. was supported by the Canadian Institutes of Health Research (CIHR FRN 477887)

Electronic properties of LaO1-xFxFeAs in the normal state probed by nmr/nqr

We report 139La, 57Fe and 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on powders of the new LaO1−xFxFeAs superconductor for x=0 and 0.1 at temperatures up to 480 K, and compare our measured NQR spectra with local density approximation (LDA) calculations. For all three nuclei in the x=0.1 material, it is found that the local Knight shift increases monotonically with an increase in temperature, and scales with the macroscopic susceptibility, suggesting a single magnetic degree of freedom. Surprisingly, the spin lattice relaxation rates for all nuclei also scale with one another, despite the fact that the form factors for each site sample different regions of q-space. This result suggests a lack of any q-space structure in the dynamical spin susceptibility that might be expected in the presence of antiferromagnetic correlations. Rather, our results are more compatible with simple quasi-particle scattering. Furthermore, we find that the increase in the electric field gradient at the As cannot be accounted for by LDA calculations, suggesting that structural changes, in particular the position of the As in the unit cell, dominate the NQR response

Random Shortest Paths: {Non-Euclidean} Instances for Metric Optimization Problems

Probabilistic analysis for metric optimization problems has mostly been conducted on random Euclidean instances, but little is known about metric instances drawn from distributions other than the Euclidean. This motivates our study of random metric instances for optimization problems obtained as follows: Every edge of a complete graph gets a weight drawn independently at random. The distance between two nodes is then the length of a shortest path (with respect to the weights drawn) that connects these nodes. We prove structural properties of the random shortest path metrics generated in this way. Our main structural contribution is the construction of a good clustering. Then we apply these findings to analyze the approximation ratios of heuristics for matching, the traveling salesman problem (TSP), and the k-median problem, as well as the running-time of the 2-opt heuristic for the TSP. The bounds that we obtain are considerably better than the respective worst-case bounds. This suggests that random shortest path metrics are easy instances, similar to random Euclidean instances, albeit for completely different structural reasons

MaxPre : An Extended MaxSAT Preprocessor

We describe MaxPre, an open-source preprocessor for (weighted partial) maximum satisfiability (MaxSAT). MaxPre implements both SAT-based and MaxSAT-specific preprocessing techniques, and offers solution reconstruction, cardinality constraint encoding, and an API for tight integration into SAT-based MaxSAT solvers.Peer reviewe

Nanoscale Electronic Order in Iron Pnictides

The charge distribution in RFeAs (R=La, Sm) iron pnictides is probed using As NQR. Whereas undoped and optimally-doped/overdoped compounds feature a single charge environment, two charge environments are detected in the underdoped region. Spin- lattice relaxation measurements show their coexistence at the nanoscale. Together with the quantitative variations of the spectra with doping, they point at a local electronic order in the iron layers, where low- and high-doping-like regions would coexist. Implications for the interplay of static magnetism and superconductivity are discussed