Effective resting-state connectivity in severe unipolar depression before and after electroconvulsive therapy

Background Electroconvulsive therapy (ECT) is one of the most effective treatments for severe depressive disorders. A recent multi-center study found no consistent changes in correlation-based (undirected) resting-state connectivity after ECT. Effective (directed) connectivity may provide more insight into the working mechanism of ECT. Objective We investigated whether there are consistent changes in effective resting-state connectivity. Methods This multi-center study included data from 189 patients suffering from severe unipolar depression and 59 healthy control participants. Longitudinal data were available for 81 patients and 24 healthy controls. We used dynamic causal modeling for resting-state functional magnetic resonance imaging to determine effective connectivity in the default mode, salience and central executive networks before and after a course of ECT. Bayesian general linear models were used to examine differences in baseline and longitudinal effective connectivity effects associated with ECT and its effectiveness. Results Compared to controls, depressed patients showed many differences in effective connectivity at baseline, which varied according to the presence of psychotic features and later treatment outcome. Additionally, effective connectivity changed after ECT, which was related to ECT effectiveness. Notably, treatment effectiveness was associated with decreasing and increasing effective connectivity from the posterior default mode network to the left and right insula, respectively. No effects were found using correlation-based (undirected) connectivity. Conclusions A beneficial response to ECT may depend on how brain regions influence each other in networks important for emotion and cognition. These findings further elucidate the working mechanisms of ECT and may provide directions for future non-invasive brain stimulation research.publishedVersio

Effective resting-state connectivity in severe unipolar depression before and after electroconvulsive therapy

BACKGROUND: Electroconvulsive therapy (ECT) is one of the most effective treatments for severe depressive disorders. A recent multi-center study found no consistent changes in correlation-based (undirected) resting-state connectivity after ECT. Effective (directed) connectivity may provide more insight into the working mechanism of ECT. OBJECTIVE: We investigated whether there are consistent changes in effective resting-state connectivity. METHODS: This multi-center study included data from 189 patients suffering from severe unipolar depression and 59 healthy control participants. Longitudinal data were available for 81 patients and 24 healthy controls. We used dynamic causal modeling for resting-state functional magnetic resonance imaging to determine effective connectivity in the default mode, salience and central executive networks before and after a course of ECT. Bayesian general linear models were used to examine differences in baseline and longitudinal effective connectivity effects associated with ECT and its effectiveness. RESULTS: Compared to controls, depressed patients showed many differences in effective connectivity at baseline, which varied according to the presence of psychotic features and later treatment outcome. Additionally, effective connectivity changed after ECT, which was related to ECT effectiveness. Notably, treatment effectiveness was associated with decreasing and increasing effective connectivity from the posterior default mode network to the left and right insula, respectively. No effects were found using correlation-based (undirected) connectivity. CONCLUSIONS: A beneficial response to ECT may depend on how brain regions influence each other in networks important for emotion and cognition. These findings further elucidate the working mechanisms of ECT and may provide directions for future non-invasive brain stimulation research

Development and validation of a multimodal neuroimaging biomarker for electroconvulsive therapy outcome in depression: A multicenter machine learning analysis

Background Electroconvulsive therapy (ECT) is the most effective intervention for patients with treatment resistant depression. A clinical decision support tool could guide patient selection to improve the overall response rate and avoid ineffective treatments with adverse effects. Initial small-scale, monocenter studies indicate that both structural magnetic resonance imaging (sMRI) and functional MRI (fMRI) biomarkers may predict ECT outcome, but it is not known whether those results can generalize to data from other centers. The objective of this study was to develop and validate neuroimaging biomarkers for ECT outcome in a multicenter setting. Methods Multimodal data (i.e. clinical, sMRI and resting-state fMRI) were collected from seven centers of the Global ECT-MRI Research Collaboration (GEMRIC). We used data from 189 depressed patients to evaluate which data modalities or combinations thereof could provide the best predictions for treatment remission (HAM-D score ⩽7) using a support vector machine classifier. Results Remission classification using a combination of gray matter volume and functional connectivity led to good performing models with average 0.82–0.83 area under the curve (AUC) when trained and tested on samples coming from the three largest centers (N = 109), and remained acceptable when validated using leave-one-site-out cross-validation (0.70–0.73 AUC). Conclusions These results show that multimodal neuroimaging data can be used to predict remission with ECT for individual patients across different treatment centers, despite significant variability in clinical characteristics across centers. Future development of a clinical decision support tool applying these biomarkers may be feasible.publishedVersio

Ordovician sponges (Porifera) and other silicifications from Baltica in Neogene and Pleistocene fluvial deposits of the Netherlands and northern Germany

Fluvial deposits of Miocene to Early Pleistocene age in Germany and the Netherlands were laid down in the delta of the Eridanos River System, but the exact provenance of this material continues to be a subject of discussion. The aim of the present study is twofold. Firstly, a comparison of Ordovician sponges in these deposits with those from northern Estonia and the St Petersburg region (Russia) demonstrates that these erratics originated from the drainage area of the Pra Neva, a tributary of the Eridanos. Secondly, the importance of Late Ordovician silicified boulders, which yield forms of preservation that are unknown in comparable fossils, preserved in situ, is outlined. Some recommendations for future studies are made

A Lower Palaeozoic 'onychophoran' reinterpreted as a pelmatozoan (stalked echinoderm) column

Onychophorans are rare fossils, but are currently the subject of renewed research activity. However, not all 'onychophorans' have been correctly identified. The specimen described herein is preserved as a natural mould in an Upper Ordovician cobble from a Quaternary glacial deposit. The 'legs' are actually elongate tubercles, arranged in irregular circlets and showing calcite cleavage; the annulations of the body are irregularly spaced. The specimen is reinterpreted as a pelmatozoan, probably crinoid, pluricolumnal. RÉSUMÉ Les onychophores sont des fossiles rares, mais font préscntement L'objet d'une activité de recherche renouvelée. Toutefois, ce ne sont pas tous les «onychophores» qui ont été correctement identifiés. Le spécimen décrit ici est préservé com me un moulage naturcl dans un caillou Ordovicien supérieur provenant d'un dépôt glaciaire quaternaire. Les «pattes» sont en fait des tubercules allongés, disposes en cercles irréguliers et montrant des clivages de calcite; les annulations du corps sont irrégulierement espacées. Le specimen est réinterpreté comme un pelmatozoaire, probablement un crinoide à plusieurs tiges. [Traduit par la rédaction

Typology and fossil assemblage of Sandbian (Ordovician) ‘baksteenkalk’: an erratic silicified limestone of Baltic origin from the northeastern Netherlands and adjacent areas of Germany

This study seeks to describe ‘baksteenkalk’, an erratic silicified bioclastic carbonate of the Upper Sandbian from the eastern part of the Netherlands. To date, baksteenkalk has received little attention among palaeontologists. This is to be regretted on two grounds. First, baksteenkalk contains a varied fossil flora and fauna comprising many species, several of which are not or only rarely found in coeval rocks. Second, owing to a complicated silicification process, fossils, in particular algae, have preserved exceptional anatomical details. The primary aim of this study is to arouse the interest of professional, in particular, Estonian, palaeontologists in baksteenkalk. Based on lithology and fossil assemblage (most conspicuously, with regard to the algal flora), two basic types of baksteenkalk are distinguished. A list of species, differentiated for both types, is provided. It is argued that baksteenkalk reflects the ecology of a shallow, subtropical, epicontinental sea. The distribution of erratics, facies and fossil content point to an origin within the North Estonian Confacies Belt, probably west of Estonia. Baksteenkalk survived as an erratic because it was already silicified at its place of origin. A potential source of silica may have been Upper Ordovician bentonite layers. The causes and mechanisms of the silicifi­cation process which gave shape to baksteenkalk are not yet understood, however. The palaeontology of baksteenkalk is compared with that of two other erratic Sandbian silicified carbonates of Baltic origin: German Backsteinkalk and ‘Lavender-blue Hornstein’