Neural correlates of causality judgment in physical and social context-The reversed effects of space and time

The perception of causal relationships is crucial to understanding and interacting with our physical and social environment. However, whether the same or different neural processes are involved in perceiving physical and social causality is unknown. Therefore, this study is focused on commonalities and differences in the neural correlates of causality perception in both contexts. During fMRI data-acquisition, participants judged causal relationships of objects in two types of animated video clips (physical/social) with similar manipulations of temporal and spatial stimulus characteristics. Four conditions were analyzed in a two-factorial design [physical causal (PC), physical non-causal (PNC), social causal (SC), social non-causal (SNC)]. We found that higher angles and longer time delays led to decreasing judgments of causality in the physical context, whereas the same manipulations led to increasing judgments in the social context. Instead of a common network for causal judgments (PC>PNC∩SC>SNC), we found a reversed activation pattern for the factors context and judgment. PC and SNC [(PC>PNC)>(SC>SNC)] produced activations in the bilateral insula, the right angular and inferior frontal gyrus and the medial supplementary motor area. PNC and SC [(PC>PNC)<(SC>SNC)] produced activity in medial frontal, left superior temporal and anterior cingulate brain regions. Our data suggest, that the same brain regions contribute to the impression of physical and social causality. However, they demonstrate a reversed activation pattern that reflects the stimulus characteristics of the respective conditions. Thus, specific stimulus characteristics are crucial for the perception of causality.     

Innate immune sensing 2.0 - from linear activation pathways to fine tuned and regulated innate immune networks

The innate immune system is based on pathogen recognition receptors that bind conserved microbial molecular structures, so called pathogen-associated molecular patterns (PAMPs). The characterization of the innate immune system was long based on a linear step-wise concept of recognition, activation pathways and effector defense mechanisms. Only more recently it was recognized that the innate immune system needs regulatory elements, sideways and crosstalks that allows it to fine tune and adapt its response. Thus, it is an emerging field within innate immunity research to try to understand how the immune outcome of innate immune sensing is regulated and why immune responses can be substantially different, even though the same PAMPs may have been 'sensed' at the surface organs such as the skin. Only the expansion of the innate immune system from 'pure' linear activation pathways to fine tuned and regulated innate immune networks allows us to integrate the generation of gradually accentuated and qualitatively different effector and tolerogenic immune responses. This article provides a review of the basic concepts and players of the innate immune system and will present some of the newer data defining the innate immune networks effectively regulating the immune homoeostasis and immune effector mechanisms with special focus on the skin as one of the organs involved in regulating the immune interface between the environment and the organism.     

Modeling pulmonary kinetics of 2-deoxy-2-[18F]fluoro-D-glucose during acute lung injury

RATIONALE AND OBJECTIVES: Dynamic positron emission tomographic imaging of the radiotracer 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) is increasingly used to assess metabolic activity of lung inflammatory cells. To analyze the kinetics of (18)F-FDG in brain and tumor tissues, the Sokoloff model has been typically used. In the lungs, however, a high blood-to-parenchymal volume ratio and (18)F-FDG distribution in edematous injured tissue could require a modified model to properly describe (18)F-FDG kinetics. MATERIALS AND METHODS: We developed and validated a new model of lung (18)F-FDG kinetics that includes an extravascular/noncellular compartment in addition to blood and (18)F-FDG precursor pools for phosphorylation. Parameters obtained from this model were compared with those obtained using the Sokoloff model. We analyzed dynamic PET data from 15 sheep with smoke or ventilator-induced lung injury. RESULTS: In the majority of injured lungs, the new model provided better fit to the data than the Sokoloff model. Rate of pulmonary (18)F-FDG net uptake and distribution volume in the precursor pool for phosphorylation correlated between the two models (R(2)=0.98, 0.78), but were overestimated with the Sokoloff model by 17% (P< .05) and 16% (P< .0005) compared to the new one. The range of the extravascular/noncellular (18)F-FDG distribution volumes was up to 13% and 49% of lung tissue volume in smoke- and ventilator-induced lung injury, respectively. CONCLUSION: The lung-specific model predicted (18)F-FDG kinetics during acute lung injury more accurately than the Sokoloff model and may provide new insights in the pathophysiology of lung injury.     

Effect of CACNA1C rs1006737 on neural correlates of verbal fluency in healthy individuals

BackgroundRecent genetic studies found the A allele of the variant rs1006737 in the alpha 1C subunit of the L-type voltage-gated calcium channel (CACNA1C) gene to be overrepresented in patients suffering from bipolar disorder, schizophrenia or major depression. While the functions underlying the pathophysiology of these psychiatric disorders are yet unknown, impaired performance in verbal fluency tasks is an often replicated finding. We investigated the influence of the rs1006737 single nucleotide polymorphism (SNP) on verbal fluency and its neural correlates.MethodsBrain activation was measured with functional magnetic resonance imaging (fMRI) during a semantic verbal fluency task in 63 healthy male individuals. They additionally performed more demanding verbal fluency tasks outside the scanner. All subjects were genotyped for CACNA1C rs1006737.ResultsFor the behavioral measures outside the scanner, rs1006737genotype had an effect on semantic but not on lexical verbal fluency with decreased performance in risk-allele carriers. In the fMRI experiment, while there were no differences in behavioural performance, increased activation in the left inferior frontal gyrus as well as the left precuneus was found in risk-allele carriers in the semantic verbal fluency task.ConclusionsThe rs1006737 variant does influence language production on a semantic level in conjunction with the underlying neural systems. These findings are in line with results of studies in bipolar disorder, schizophrenia and major depression and may explain some of the cognitive and brain activation variation found in these disorders.     

Human Fear Conditioning and Extinction in Neuroimaging: A Systematic Review

Fear conditioning and extinction are basic forms of associative learning that have gained considerable clinical relevance in enhancing our understanding of anxiety disorders and facilitating their treatment. Modern neuroimaging techniques have significantly aided the identification of anatomical structures and networks involved in fear conditioning. On closer inspection, there is considerable variation in methodology and results between studies. This systematic review provides an overview of the current neuroimaging literature on fear conditioning and extinction on healthy subjects, taking into account methodological issues such as the conditioning paradigm.     

Effect of leak around the endotracheal tube on measurements of pulmonary compliance and resistance during mechanical ventilation: A lung model study

We studied the effect of leaks around the endotracheal tube (ETT) on the measurement of pulmonary mechanics during mechanical ventilation. We also evaluated the influence of different ventilator settings on the magnitude of leak. An adjustable leak was created at the end of the ETT in a lung model with constant compliance. Flow, tidal volume, and pressure changes were measured above and below the leak. Compliance (C_i) and resistance (R_i) during inspiration were determined by linear regression analysis (LRA) using the equation of motion and the Mead and Wittenberger method (MWM). The ventilatory change that influenced the degree of leak most was prolongation of inspiratory time (T_i). The presence of a leak around the ETT resulted in an overestimation of the C_i and R_i values, which was proportional to the size of the leak. This overestimation was also influenced by the method used to determine C_i and R_i. Because the contribution of the leak to the tidal volume progressively increased as inspiration continued, methods of analysis that depended mainly on measurement points at the end of inspiration showed a larger deviation from the true C_i and R_i values than methods mainly influenced by measurement points at the beginning of inspiration. Because of this, shortening of inspiration, or analysis of points at the beginning of inspiration reduces the error in the measurements of C_i and R_i when a leak is present. Breaths with a large leak should be excluded from any analysis of pulmonary mechanics. Pediatr Pulmonol. 1996; 22:35–43. © 1996 Wiley-Liss, Inc.     

Outcome of the frozen elephant trunk procedure as a redo operation

 Open in a separate windowOBJECTIVESThe goal of this study was to determine the outcome of patients undergoing an elective frozen elephant trunk (FET) procedure as a redo operation following previous cardiac surgery.METHODSOne hundred and eighteen consecutive patients underwent FET procedures between October 2010 and October 2019 at our centre. Patients were registered in a dedicated database and analysed retrospectively. Clinical and follow-up characteristics were compared between patients undergoing a FET operation as a primary (primary group) or a redo procedure (redo group) using logistic regression and Cox regression analysis. Emergency procedures (n = 33) were excluded from the analysis.RESULTSA total of 36.5% (n = 31) of the FET procedures were redo operations (redo group) and 63.5% (n = 54) of the patients underwent primary surgery (primary group). There was no significant difference in the 30-day mortality [primary group: 7.4%; redo group: 3.2%; 95% confidence interval (CI) (0.19–35.29); P = 0.63] and the 3-year mortality [primary group: 22.2%; redo group: 16.7%; 95% CI (0.23–3.23); P = 0.72] between redo and primary cases. Furthermore, the adjusted statistical analysis did not reveal significant differences between the groups in the occurrence of transient or permanent neurological deficit, paraplegia, acute renal failure and resternotomy. The redo group showed a higher rate of recurrent nerve palsy, which did not reach statistical significance [primary group: 3.7% (n = 2); redo group: 19.4% (n = 6); P = 0.091].CONCLUSIONSElective FET procedures as redo operations performed by a dedicated aortic team following previous cardiac surgery demonstrate an adequate safety profile.     

Single-center experience with an inner branched arch endograft

Objective

Whereas open repair is the “gold standard” for most aortic arch diseases, a subgroup of patients might benefit from an endovascular approach. The introduction of branched stent grafts with dedicated design to address the challenges of the ascending aorta and the aortic arch has opened an entirely new area of treatment for these patients. We investigated the early outcomes of branched thoracic endovascular aortic repair (b-TEVAR) in various types of disease of the aortic arch.