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A unified 3D reconstruction of microscopy and MRI in a brain showing Alzheimer's disease‐related neuropathology
Get PDFTo bridge between detailed post-mortem neuropathological assessments and Magnetic Resonance Imaging (MRI), we have created and share a three-dimensional (3D) account of an entire human brain with an intermediate Alzheimer's disease neuropathologic change. We combined multimodal imaging, using cryosectioning, histology, immunocytochemistry, and quantitative ultra-high field 7 Tesla (T) magnetic resonance imaging (MRI) at submillimeter resolution. Amyloid-β and phosphorylated-tau immunoreactivity, cell soma, and nerve fibers were visualized, together with quantitative MR parameters. All data were coaligned with at 200 μm resolution and are openly shared. The use of whole-brain sections allows for a detailed assessment of neuropathological alterations, revealing clear differences between the left and right hemispheres in terms of pathological load of amyloid-β and phosphorylated-tau in a single brain showing Alzheimer's disease neuropathologic change. This resource opens the door for a combination of detailed correlations between neuroimaging and neuropathological microscopy observations, as well as for detailed MRI validation
New control of the 50-years-old flywheel generator EZ2 – a necessary update to the latest industrial state of the art for the toridal field of ASDEX upgrade
No full textNetwork mechanisms in rapid-onset dystonia-parkinsonism
Get PDFRapid-onset dystonia-parkinsonism (RDP) is a rare neurological disorder caused by mutations in the ATP1A3 gene. Symptoms are characterized by a dystonia-parkinsonism. Recently, experimental studies have shown that the pathophysiology of the disease is based on a combined dysfunction of the cerebellum (CB) and basal ganglia (BG) and that blocking their interaction can alleviate the symptoms. The underlying network mechanisms have not been studied so far. Our aim was to characterize neuronal network activity in the BG and CB and motor cortex in the ouabain model of RDP by site-specific infusion of ouabain. Rats were chronically infused with ouabain either in the CB, striatum (STR) or at both places simultaneously. Motor behavior was scored using published rating systems. Parallel in vivo recordings of local field potentials (LFP) from M1, deep cerebellar nuclei (DCN) and substantia nigra reticulata (SNr) were performed. Data were compared to untreated controls. Ouabain infusion into the cerebellum produced severe dystonia that was associated with increased high-frequency gamma oscillations in the DCNs, which were subsequently transmitted to the BG and M1. Striatal infusion led to parkinsonism and elevated beta-oscillations in SNr that were transmitted to the CB and M1. The simultaneous application of STRs and CB with ouabain resulted in dystonia-parkinsonism and increased beta oscillations in BG, CB, and M1.We demonstrate that symptom-specific beta and gamma oscillations can be transmitted between the BG and CB, which is likely to be very important for the understanding of disease mechanisms
The process structure of memory abilities in early and middle childhood [Registered Report]
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Graph Neural Networks embedded into Margules model for vapor-liquid equilibria prediction
Get PDFPredictive thermodynamic models are crucial for the early stages of productand process design. In this paper the performance of Graph Neural Networks(GNNs) embedded into a relatively simple excess Gibbs energy model, theextended Margules model, for predicting vapor-liquid equilibrium is analyzed.By comparing its performance against the established UNIFAC-Dortmund model ithas been shown that GNNs embedded in Margules achieves an overall loweraccuracy. However, higher accuracy is observed in the case of various types ofbinary mixtures. Moreover, since group contribution methods, like UNIFAC, arelimited due to feasibility of molecular fragmentation or availability ofparameters, the GNN in Margules model offers an alternative for VLE estimation.The findings establish a baseline for the predictive accuracy that simpleexcess Gibbs energy models combined with GNNs trained solely on infinitedilution data can achieve.<br
Constructing language: A framework for explaining acquisition
Get PDFExplaining how children build a language system is a central goal of research in language acquisition, with broad implications for language evolution, adult language processing, and artificial intelligence (AI). Here, we propose a constructivist framework for future theory-building in language acquisition. We describe four components of constructivism, drawing on wide-ranging evidence to argue that theories based on these components will be well suited to explaining developmental change. We show how adopting a constructivist framework both provides plausible answers to old questions (e.g., how children build linguistic representations from their input) and generates new questions (e.g., how children adapt to the affordances provided by different cultures and languages)
Nonsymmetric -Cauchy identity and representations of the Iwahori algebra
Get PDFThe t=0 specialization of the Mimachi-Noumi Cauchy-type identity rewrites certain infinite product in terms of specialized nonsymmetric Macdonald polynomials of type GLn. We interpret the infinite product as a character of the space of functions on a certain matrix space. We show that the space of functions admits a filtration such that the graded pieces are isomorphic to the tensor products of certain generalized global Weyl modules of the Iwahori algebra. We identify the characters of the graded pieces with the terms of the specialized Mimachi-Noumi formula. We conjecture the existence of an analogous filtration on the space of functions on the Iwahori group for all simple Lie algebras and prove the conjecture for SLn. Our construction can be seen as a current algebra extension of the van der Kallen filtration on functions on a Borel subgroup
Modeling 2D spatio-tactile population receptive fields of the fingertip in human primary somatosensory cortex
Get PDFTactile fingertip sensations are critical for everyday life. Accordingly, tac- tile fingertip maps have been extensively studied in human primary somatosensory cor- tex. However, the fine-grained functional architecture of these maps remains largely unknown. To uncover this architecture, we sought to estimate 2D spatio-tactile pop- ulation receptive fields (pRFs) of the tip of the index finger in human Brodmann area 3b (BA3b). Using functional magnetic resonance imaging at 7T and submillimeter resolution along with prospective motion correction, we recorded brain responses whilst participants sensed a row of vibrotactile pins sweeping along cardinal axes over a portion of the fingertip. To estimate pRF position and size, we initially fit a 2D Gaussian pRF model to the data, which, however, produced largely implausible pRF estimates. Sim- ulations indicated that this likely occurred because the size of pRFs in BA3b surpasses the portion of the fingertip we stimulated, resulting in an incomplete mapping of pRFs. To address this issue, we constrained the fitting procedure and refined the 2D Gaussian pRF model by keeping pRF size constant. Our results for pRF position then revealed that the ulnar-to-radial axis spanning the fingertip maps onto a superior-to-inferior axis in BA3b. Both the putatively large pRF size (relative to the mapping area) and the pRF position gradient we uncover here appear compatible with receptive field properties quantified in monkeys. Our study provides the first comprehensive investigation into the fine-grained functional architecture of human fingertip maps and brings us one step closer to a thorough understanding thereof
