Ventral striatum gray matter density reduction in patients with schizophrenia and psychotic emotional dysregulation

INTRODUCTION: Substantial heterogeneity remains across studies investigating changes in gray matter in schizophrenia. Differences in methodology, heterogeneous symptom patterns and symptom trajectories may contribute to inconsistent findings. To address this problem, we recently proposed to group patients by symptom dimensions, which map on the language, the limbic and the motor systems. The aim of the present study was to investigate whether patients with prevalent symptoms of emotional dysregulation would show structural neuronal abnormalities in the limbic system. METHOD: 43 right-handed medicated patients with schizophrenia were assessed with the Bern Psychopathology Scale (BPS). The patients and a control group of 34 healthy individuals underwent structural imaging at a 3T MRI scanner. Whole brain voxel-based morphometry (VBM) was compared between patient subgroups with different severity of emotional dysregulation. Group comparisons (comparison between patients with severe emotional dysregulation, patients with mild emotional dysregulation, patients with no emotional dysregulation and healthy controls) were performed using a one way ANOVA and ANCOVA respectively. RESULTS: Patients with severe emotional dysregulation had significantly decreased gray matter density in a large cluster including the right ventral striatum and the head of the caudate compared to patients without emotional dysregulation. Comparing patients with severe emotional dysregulation and healthy controls, several clusters of significant decreased GM density were detected in patients, including the right ventral striatum, head of the caudate, left hippocampus, bilateral thalamus, dorsolateral prefrontal and orbitofrontal cortex. The significant effect in the ventral striatum was lost when patients with and without emotional dysregulation were pooled and compared with controls. DISCUSSION: Decreased gray matter density in a large cluster including the right ventral striatum was associated with severe symptoms of emotional dysregulation in patients with schizophrenia. The ventral striatum is an important part of the limbic system, and was indicated to be involved in the generation of incentive salience and psychotic symptoms. Only patients with severe emotional dysregulation had decreased gray matter in several brain structures associated with emotion and reward processing compared to healthy controls. The results support the hypothesis that grouping patients according to specific clinical symptoms matched to the limbic system allows identifying patient subgroups with structural abnormalities in the limbic network.

Der schweizerische Bundesstaat von 1848 bis 1874: Mehrheits- oder Konsensusdemokratie?

Der vorliegende Beitrag geht der Frage nach, ob die schweizerische Demokratie bereits ab der Bundesstaatsgründung im Jahr 1848 eine ausgeprägte Konsensusdemokratie war. Zur Beantwortung dieser Fragestellung bedient sich die Studie des Konzepts von Arend Lijphart (2012) mit der Unterscheidung von Mehrheits- und Konsensusdemokratie. Anhand von Literatur- und Dokumentenanalysen wurden Lijpharts Indikatoren für den schweizerischen Bundesstaat von 1848–1874 codiert. Die Ergebnisse zeigen, dass das politische System der neu gegründeten Schweiz auf Lijpharts Demokratiekarte insbesondere auf der horizontalen Machtteilungsdimension wie erwartet sehr nahe an der Position der USA zu liegen kommt.

Familia honor y poder. La nobleza de la ciudad de Quito durante la época colonial tardía (1765- 1822)

Con este trabajo sobre la nobleza de la ciudad de Quito, Christian Büschges amplía el campo de los estudios socio-económicos y políticos sobre las así llamadas élites coloniales, con un análisis que se enfoca de manera especial en las mentalidades y representaciones estamentales, que tan fuertemente marcaron las relaciones sociales del antiguo régimen colonial.

DTI and VBM reveal white matter changes without associated gray matter changes in patients with idiopathic restless legs syndrome

BACKGROUND AND PURPOSE We evaluated cerebral white and gray matter changes in patients with iRLS in order to shed light on the pathophysiology of this disease. METHODS Twelve patients with iRLS were compared to 12 age- and sex-matched controls using whole-head diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) techniques. Evaluation of the DTI scans included the voxelwise analysis of the fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD). RESULTS Diffusion tensor imaging revealed areas of altered FA in subcortical white matter bilaterally, mainly in temporal regions as well as in the right internal capsule, the pons, and the right cerebellum. These changes overlapped with changes in RD. Voxel-based morphometry did not reveal any gray matter alterations. CONCLUSIONS We showed altered diffusion properties in several white matter regions in patients with iRLS. White matter changes could mainly be attributed to changes in RD, a parameter thought to reflect altered myelination. Areas with altered white matter microstructure included areas in the internal capsule which include the corticospinal tract to the lower limbs, thereby supporting studies that suggest changes in sensorimotor pathways associated with RLS.