Gaze direction affects linear self‐motion heading discrimination in humans

We investigated the effect of eye‐in‐head and head‐on‐trunk direction on heading discrimination. Participants were passively translated in darkness along linear trajectories in the horizontal plane deviating 2° or 5° to the right or left of straight‐ahead as defined by the subject's trunk. Participants had to report whether the experienced translation was to the right or left of the trunk straight‐ahead. In a first set of experiments, the head was centered on the trunk and fixation lights directed the eyes 16° either left or right. Although eye position was not correlated with the direction of translation, rightward reports were more frequent when looking right than when looking left, a shift of the point of subjective equivalence in the direction opposite to eye direction (two of the 38 participants showed the opposite effect). In a second experiment, subjects had to judge the same trunk‐referenced trajectories with head‐on‐trunk deviated 16° left. Comparison with the performance in the head‐centered paradigms showed an effect of the head in the same direction as the effect of eye eccentricity. These results can be qualitatively described by biases reflecting statistical regularities present in human behaviors such as the alignment of gaze and path. Given the known effects of gaze on auditory localization and perception of straight‐ahead, we also expect contributions from a general influence of gaze on the head‐to‐trunk reference frame transformations needed to bring motion‐related information from the head‐centered otoliths into a trunk‐referenced representation.     

Discriminating unipolar and bipolar depression by means of fMRI and pattern classification: a pilot study

Bipolar disorders rank among the most debilitating psychiatric diseases. Bipolar depression is often misdiagnosed as unipolar depression, leading to suboptimal therapy and poor outcomes. Discriminating unipolar and bipolar depression at earlier stages of illness could therefore help to facilitate efficient and specific treatment. In the present study, the neurobiological underpinnings of emotion processing were investigated in a sample of unipolar and bipolar depressed patients matched for age, gender, and depression severity by means of fMRI. A pattern-classification approach was employed to discriminate the two samples. The pattern classification yielded up to 90 % accuracy rates discriminating the two groups. According to the feature weights of the multivariate maps, medial prefrontal and orbitofrontal regions contributed to classifications specific to unipolar depression, whereas stronger feature weights in dorsolateral prefrontal areas contribute to classifications as bipolar. Strong feature weights were observed in the amygdala for the negative faces condition, which were specific to unipolar depression, whereas higher amygdala features weights during the positive faces condition were observed, specific to bipolar subjects. Standard univariate fMRI analysis supports an interpretation, where this might be related to a higher responsiveness, by yielding a significant emotion × group interaction within the bilateral amygdala. We conclude that pattern-classification techniques could be a promising tool to classify acutely depressed subjects as unipolar or bipolar. However, since the present approach deals with small sample sizes, it should be considered as a proof-of-concept study. Hence, results have to be confirmed in larger samples preferably of unmedicated subjects.     

FreeSurfer-based segmentation of hippocampal subfields: A review of methods and applications,with a novel quality control procedure for ENIGMA studies and other collaborative efforts

Structural hippocampal abnormalities are common in many neurological and psychiatric disorders, and variation in hippocampal measures is related to cognitive performance and other complex phenotypes such as stress sensitivity. Hippocampal subregions are increasingly studied, as automated algorithms have become available for mapping and volume quantification. In the context of the Enhancing Neuro Imaging Genetics through Meta Analysis Consortium, several Disease Working Groups are using the FreeSurfer software to analyze hippocampal subregion (subfield) volumes in patients with neurological and psychiatric conditions along with data from matched controls. In this overview, we explain the algorithm's principles, summarize measurement reliability studies, and demonstrate two additional aspects (subfield autocorrelation and volume/reliability correlation) with illustrative data. We then explain the rationale for a standardized hippocampal subfield segmentation quality control (QC) procedure for improved pipeline harmonization. To guide researchers to make optimal use of the algorithm, we discuss how global size and age effects can be modeled, how QC steps can be incorporated and how subfields may be aggregated into composite volumes. This discussion is based on a synopsis of 162 published neuroimaging studies (01/2013–12/2019) that applied the FreeSurfer hippocampal subfield segmentation in a broad range of domains including cognition and healthy aging, brain development and neurodegeneration, affective disorders, psychosis, stress regulation, neurotoxicity, epilepsy, inflammatory disease, childhood adversity and posttraumatic stress disorder, and candidate and whole genome (epi-)genetics. Finally, we highlight points where FreeSurfer-based hippocampal subfield studies may be optimized.     

O2-Therapie im Notfall – Time to say goodbye?

Notfall + Rettungsmedizin - Die O2-Inhalationstherapie gehört zu den Standardmaßnahmen der Notfallmedizin und wird zunehmend kritisch diskutiert. Pathophysiologische Überlegungen und...     

Das weltweite Medizinernetzwerk Aufklärung gegen Tabak – Ehrenamtliche Prävention made in Germany

Smoking is the leading preventable cause of premature death in Germany. The network “Education Against Tobacco” (EAT) is an initiative that was founded in Germany in 2012, in which more than 3500 medical students and physicians engage in volunteer work in about 80 medical faculties in 14 countries. In this article, the concept, activities, objectives and associated research studies oft he EAT initiative are introduced.On the school level, the initiative addresses 10- to 15-year-old secondary school students. In addition to a multimodal approach, school visits use modern media such as facemorphing apps, which are not only used by students (45,000 per year in 14 countries), but by a total of over 500,000 other people as well. The effectiveness of the school-based intervention is currently being investigated in randomised long-term studies with 20,000 adolescents in Germany. A first long-term study demonstrated evidence of a protective effect regarding the onset of smoking, especially among female students, students having a low level of education and students with a migratory background.The programme educates several hundred prospective physicians at 13 (of 28 participating) German medical faculties each year in science-based elective courses for the well-established smoking cessation counselling of patients and sensitises them to the tobacco epidemic. The approved members engage in dialogue with local members of the German house of representatives as “Ärzteverband Tabakprävention”.EAT motivates the prospective generation of physicians, initially through prevention in school settings, to face the challenge of national tobacco control at the university and federal level.     

A new method for cerclage wire fixation to maximal pre-tension with minimal elongation to failure

Objective. To develop and test a new cerclage wire tightening technique, yielding reproducibly maximal pre-tension, load to failure and minimal elongation to failure of the wire junction.

Design. Laboratory bench study.

Background. Cerclage wire fixation is difficult to perform by hand with reproducible quality and tightening tension, which are required for optimal performance.

Methods. With the new technique, 1, 1.25 and 1.5 mm steel wires were passed through a 9 × 18 mm steel tube, grasped using a modified ASIF wire-tightener and tightened by twisting until spontaneous failure of the wires in the tube. These fixations were compared to wires pre-tightened by hand to controlled high or low pre-tension using the simple twist, the knot twist and twist secured against untwisting, loaded to failure on a testing machine. The tests assessed pre-tension, ultimate failure load and elongation to failure.

Results. Wire twists performed with the new technique were always perfectly symmetrical and may be tightened to maximal pre-tension without weakening of the wire. The twist secured against untwisting combined high stiffness with high failure load.

The knot twist elongates to an unacceptable degree, unlike the secured twist. The simple twist untwists under little tension.

Conclusions. The new technique allows to obtain maximal pre-tension and thus minimal elongation to failure of simple wire twists, without having to worry about breaking the wire at the base of the twist due to over-tightening.Relevance

Cerclage wire fixation is an effective and cheap method to perform osteosynthesis. For adequate performance, maximal pre-tension, symmetrical twisting and high load to failure are necessary. The here presented technique combines all of these pre-requisites in a simple fashion.     

Acute oxygenator occlusion in two cases of polycythemia vera: Bailout strategies

Polycytemia vera (PV) is a rare myeloproliferative neoplasm associated with microcirculatory disturbances, thrombosis and bleeding. Patients suffering from PV have a high risk of perioperative adverse events, but the literature regarding on-pump procedures in PV patients is scarce. We report two cases of acute and severe oxygenator failure during cardiopulmonary bypass and present valid exit scenarios.