Visual information is organised according to visual grouping principles. In visual grouping tasks individuals with ASD have shown equivocal performance. We explored neural correlates of Gestalt ...grouping in individuals with and without ASD. Neuromagnetic activity of individuals with (15) and without (18) ASD was compared during a visual grouping task testing grouping by proximity versus similarity. Individuals without ASD showed stronger evoked responses with earlier peaks in response to both grouping types indicating an earlier neuronal differentiation between grouping principles in individuals without ASD. In contrast, individuals with ASD showed particularly prolonged processing of grouping by similarity suggesting a high demand of neural resources. The neuronal processing differences found could explain less efficient grouping performance observed behaviourally in ASD.
Neural fingerprinting is the identification of individuals in a cohort based on neuroimaging recordings of brain activity. In magneto- and electroencephalography (M/EEG), it is common practice to use ...second-order statistical measures, such as correlation or connectivity matrices, when neural fingerprinting is performed. These measures or features typically require coupling between signal channels and often ignore the individual temporal dynamics. In this study, we show that, following recent advances in multivariate time series classification, such as the development of the RandOm Convolutional KErnel Transformation (ROCKET) classifier, it is possible to perform classification directly on short time segments from MEG resting-state recordings with remarkably high classification accuracies. In a cohort of 124 subjects, it was possible to assign windows of time series of 1 s in duration to the correct subject with above 99% accuracy. The achieved accuracies are vastly superior to those of previous methods while simultaneously requiring considerably shorter time segments.
A key step in the de novo formation of the embryonic vasculature is the migration of endothelial precursors, the angioblasts, to the position of the future vessels. To form the first axial vessels, ...angioblasts migrate towards the midline and coalesce underneath the notochord. Vascular endothelial growth factor has been proposed to serve as a chemoattractant for the angioblasts and to regulate this medial migration. Here we challenge this model and instead demonstrate that angioblasts rely on their intrinsic expression of Apelin receptors (Aplr, APJ) for their migration to the midline. We further show that during this angioblast migration Apelin receptor signaling is mainly triggered by the recently discovered ligand Elabela (Ela). As neither of the ligands Ela or Apelin (Apln) nor their receptors have previously been implicated in regulating angioblast migration, we hereby provide a novel mechanism for regulating vasculogenesis, with direct relevance to physiological and pathological angiogenesis.
The cognitive impact of psychological trauma can manifest as a range of post-traumatic stress symptoms that are often attributed to impairments in learning from positive and negative outcomes, aka ...reinforcement learning. Research on the impact of trauma on reinforcement learning has mainly been inconclusive. This study aimed to circumscribe the impact of psychological trauma on reinforcement learning in the context of neural response in time and frequency domains. Two groups of participants were tested - those who had experienced psychological trauma and a control group who had not - while they performed a probabilistic classification task that dissociates learning from positive and negative feedback during a magnetoencephalography (MEG) examination. While the exposure to trauma did not exhibit any effects on learning accuracy or response time for positive or negative feedback, MEG cortical activity was modulated in response to positive feedback. In particular, the medial and lateral orbitofrontal cortices (mOFC and lOFC) exhibited increased activity, while the insular and supramarginal cortices showed decreased activity during positive feedback presentation. Furthermore, when receiving negative feedback, the trauma group displayed higher activity in the medial portion of the superior frontal cortex. The timing of these activity changes occurred between 160 and 600 ms post feedback presentation. Analysis of the time-frequency domain revealed heightened activity in theta and alpha frequency bands (4–10 Hz) in the lOFC in the trauma group. Moreover, dividing the two groups according to their learning performance, the activity for the non-learner subgroup was found to be lower in lOFC and higher in the supramarginal cortex. These differences were found in the trauma group only. The results highlight the localization and neural dynamics of feedback processing that could be affected by exposure to psychological trauma. This approach and associated findings provide a novel framework for understanding the cognitive correlates of psychological trauma in relation to neural dynamics in the space, time, and frequency domains. Subsequent work will focus on the stratification of cognitive and neural correlates as a function of various symptoms of psychological trauma. Clinically, the study findings and approach open the possibility for neuromodulation interventions that synchronize cognitive and psychological constructs for individualized treatment.
In our daily lives, we use eye movements to actively sample visual information from our environment ("active vision"). However, little is known about how the underlying mechanisms are affected by ...goal-directed behavior. In a study of 31 participants, magnetoencephalography was combined with eye-tracking technology to investigate how interregional interactions in the brain change when engaged in two distinct forms of active vision: freely viewing natural images or performing a guided visual search. Regions of interest with significant fixation-related evoked activity (FRA) were identified with spatiotemporal cluster permutation testing. Using generalized partial directed coherence, we show that, in response to fixation onset, a bilateral cluster consisting of four regions (posterior insula, transverse temporal gyri, superior temporal gyrus, and supramarginal gyrus) formed a highly connected network during free viewing. A comparable network also emerged in the right hemisphere during the search task, with the right supramarginal gyrus acting as a central node for information exchange. The results suggest that all four regions are vital to visual processing and guiding attention. Furthermore, the right supramarginal gyrus was the only region where activity during fixations on the search target was significantly negatively correlated with search response times. Based on our findings, we hypothesize that, following a fixation, the right supramarginal gyrus supplies the right supplementary eye field (SEF) with new information to update the priority map guiding the eye movements during the search task.
Background
Impaired decision making, a key characteristic of alcohol dependence (AD), manifests in continuous alcohol consumption despite severe negative consequences. The neural basis of this ...impairment in individuals with AD and differences with known neural decision mechanisms among healthy subjects are not fully understood. In particular, it is unclear whether the choice behavior among individuals with AD is based on a general impairment of decision mechanisms or is mainly explained by altered value attribution, with an overly high subjective value attributed to alcohol‐related stimuli.
Methods
Here, we use a functional magnetic resonance imaging (fMRI) monetary reward task to compare the neural processes of model‐based decision making and value computation between AD individuals (n = 32) and healthy controls (n = 32). During fMRI, participants evaluated monetary offers with respect to dynamically changing constraints and different levels of uncertainty.
Results
Individuals with AD showed lower activation associated with model‐based decision processes in the caudate nucleus than controls, but there were no group differences in value‐related neural activity or task performance.
Conclusions
Our findings highlight the role of the caudate nucleus in impaired model‐based decisions of alcohol‐dependent individuals.
Impairment of decision‐making is a key characteristic of alcohol dependence, but the neural basis and differences to decision mechanisms of healthy subjects are still not fully understood. Here we use an fMRI monetary reward task to compare neural processes of model‐based decision‐making and value computation between patients and controls. Patients showed decreased activation associated with model‐based decision processes in caudate nucleus, but there were no value‐related or behavioral differences between groups, highlighting the role of the caudate in impaired decisions of patients.
Extensive surgical efforts to achieve an optimal debulking (no residual tumor) in primary surgery of ovarian cancer are today's criterion standard in gyneco-oncologic surgery. However, it is ...controversial whether extensive surgery, including resections of metastases in the upper abdomen and bowel resections, is justifiable in patients with not completely operable lesions.
All patients who had undergone surgery for ovarian cancer in the years 2002 to 2013 at our institution were viewed (n = 472). We retrospectively identified 278 operations for primary ovarian cancer. Ninety-six (35%) of the 278 patients showed postoperative tumor residuals and were included in this study.
Fifty-five (57%) of 96 patients underwent bowel resection, showing significantly higher complication rates (64% vs 39% minor complications, P = 0.017; 31% vs 9.8% severe complications, P = 0.013) compared with patients without bowel resections as well as no improvement in progression-free or overall survival (median overall survival, 19.5 vs 32.9; P = 0.382). Multiple anastomoses (≥2) were associated with higher rates for anastomotic leakage (16.7% vs 2.6%, P = 0.02) and a higher mortality (16.7% vs 0%, P = 0.04) compared with patients with only 1 anastomosis. Extensive surgery of the upper abdomen was not associated with a significant increase in complication rates.
Because of the increased morbidity of bowel resections without any evidence for improvement of survival, we suggest to restrain from further resection of intestines if an optimal debulking seems not feasible after removal of the major tumor bulk.
Background In the past, chordal replacement techniques with expanded polytetrafluoroethylene sutures have been primarily reserved for anterior leaflet pathology, whereas the more frequent posterior ...leaflet prolapse was treated by resection. This study reports midterm results of isolated posterior prolapse repair with chordal replacement without resection as opposed to the quadrangular resection. Methods An analysis was made of 397 consecutive patients who underwent mitral valve repair for isolated posterior leaflet prolapse between 2000 and 2007. Of them, 205 patients (52%) underwent quadrangular resection (group R, “resection”) and 192 patients (48%) underwent a neochordal repair (group NR, “no resection”). The follow-up is 98% complete (mean follow-up of 383 survivors is 1.9 ± 1.4 years). Results Overall 30-day mortality was 1.0% (4 of 397). Ten patients (2.5%) died late. Actuarial survival at 4 years for group R and group NR was 94% ± 3% and 98% ± 1%, respectively ( p = 0.99). Ten patients (2.5%) required a mitral valve–related reoperation after an average of 1.9 ± 2 months. Freedom from reoperation at 4 years was 96% ± 1% for group R and 99% ± 1% for group NR ( p = 0.08). Generally, in patients of group NR, a larger annuloplasty ring could be implanted (mean size 32 ± 2.5 versus 30 ± 2, p < 0.001). At latest follow-up, 94% of the patients showed no or grade I regurgitation, with no difference between groups. Conclusions Repair of posterior mitral leaflet prolapse by chordal replacement is equally effective as classic quadrangular resection, permits the use of larger annuloplasty rings, offers a potentially more physiological repair with preserved leaflet mobility, and can be performed with excellent midterm results and a low incidence of reoperation.
Abstract Background Composite tissue allotransplantation (CTA) was introduced as a potential treatment for complex reconstructive procedures and has become a clinical reality. Hand and face ...transplantation, the most widely recognized forms of CTA, have intensified immunological research in this emerging field of transplantation. Mitomycin C (MMC) is an alkylating agent that suppresses allogeneic T-cell responses. MMC-treated dendritic cells/PBMCs have been shown to induce donor-specific tolerance in solid organ allograft transplantations. Methods Fully mismatched rats were used as hind limb donors Lewis (RT11 ) and recipients Brown-Norway (RT1n ). Fifty-five allogeneic hind limb transplantations were accomplished in six groups. Group A ( n = 10) received donor-derived MMC-treated PBMCs on transplantation day. Group B ( n = 10) rats received no immunosuppression, group C ( n = 10) received FK506 and prednisolon, group D consisted in isograft transplantation without immunosuppression, group E ( n = 10) received non-treated PBMCs, and group F ( n = 5) received PBS without any donor-derived cells. Rejection was assessed clinically and histologically. Results In group A, the survival times of the allografts were prolonged to an average of 8.0 d. Rejection was significantly delayed compared with the averages of the corresponding control groups B, E, and F (5.5, 5.9, and 5.8 d). No rejection was seen in control groups C and D. Conclusion These results demonstrate that MMC-treated donor PBMCs significantly prolong allograft survival when administered systemically on the day of transplantation. However, the immunomodulatory effect is relatively modest with further research being required to clarify dose–effect relations, cell characteristics, and an optimized mechanism and timing for cell application.
Objective Various devices have been proposed for ring stabilization in patients with mitral valve disease. This study reports the intermediate-term results of mitral valve repair with a new semirigid ...partial annuloplasty ring in a large series of patients. Methods A total of 437 consecutive patients were analyzed who underwent mitral valve reconstruction with annuloplasty using the Colvin–Galloway Future band at the German Heart Center in Munich between 2001 and 2005. A total of 237 patients (54.2%) underwent isolated mitral valve repair, and 200 patients (45.8%) underwent a combined procedure. The follow-up is 97% complete (mean follow-up of 405 survivors 2.1 ± 1.1 years). Results Overall 30-day mortality was 2.7%. Twenty patients (4.6%) died later after an average of 1.1 ± 1.1 years. Actuarial survival at 4 years after isolated mitral valve reconstruction and combined procedures was 91% ± 4% and 87% ± 2.5%, respectively ( P < .001). Twelve patients (2.7%) required a mitral valve reoperation after an average of 4.5 ± 4.3 months. Five of these reoperations were required for band dehiscence, and 1 reoperation was required for band fracture. Freedom from reoperation at 4 years was 97% ± 0.9%. At the latest follow-up, 93.5% of the patients showed trivial or mild mitral valve regurgitation, and 86.4% of the patients showed New York Heart Association functional class I or II. Conclusion Mitral valve annuloplasty with the Colvin–Galloway Future band can be performed with a low early and late mortality and an excellent functional outcome. The low incidence of reoperation demonstrates that the Colvin–Galloway Future band is a safe and effective device. The importance of secure anchoring of the device in the mitral annulus has to be emphasized to prevent band dehiscence.
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