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Cortical modeling

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https://www.readbyqxmd.com/read/29143946/multi-scale-account-of-the-network-structure-of-macaque-visual-cortex
#1
Maximilian Schmidt, Rembrandt Bakker, Claus C Hilgetag, Markus Diesmann, Sacha J van Albada
Cortical network structure has been extensively characterized at the level of local circuits and in terms of long-range connectivity, but seldom in a manner that integrates both of these scales. Furthermore, while the connectivity of cortex is known to be related to its architecture, this knowledge has not been used to derive a comprehensive cortical connectivity map. In this study, we integrate data on cortical architecture and axonal tracing data into a consistent multi-scale framework of the structure of one hemisphere of macaque vision-related cortex...
November 16, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/29143443/multiscale-characterisation-of-cortical-bone-composition-microstructure-and-nanomechanical-properties-in-experimentally-induced-osteoporosis
#2
Furqan A Shah, Adrian Stoica, Carina Cardemil, Anders Palmquist
Cortical bone plays a vital role in determining overall bone strength. We investigate the structural, compositional, and nanomechanical properties of cortical bone following ovariectomy (OVX) of 12 week old Sprague Dawley rats, since this animal model is frequently employed to evaluate the performance of implantable biomaterials in compromised bone healing conditions. Morphological parameters and material properties of bone in the geometrical centre of the femoral cortex were investigated four and eight weeks post-OVX and in unoperated controls (Ctrl), using X-ray micro-computed tomography, backscattered electron scanning electron microscopy, Raman spectroscopy, and nanoindentation...
November 16, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/29143363/utility-of-shear-wave-elastography-for-assessing-allograft-fibrosis-in-renal-transplant-recipients-a-pilot-study
#3
Heather M Early, Ellen C Cheang, Jorge M Aguilera, Jonah S W Hirschbein, Ghaneh Fananapazir, Machelle D Wilson, John P McGahan
OBJECTIVES: To evaluate the utility of ultrasound-based shear wave elastography (SWE) as a noninvasive method to accurately detect and potentially stage the severity of renal allograft fibrosis and assess its user reproducibility. METHODS: In this Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant prospective study, 70 renal transplant recipients underwent an SWE evaluation of their allograft followed directly by biopsy...
November 16, 2017: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
https://www.readbyqxmd.com/read/29142619/the-formation-of-extragraft-bone-bridging-after-anterior-cervical-discectomy-and-fusion-a-finite-element-analysis
#4
Shin Won Kwon, Chi Heon Kim, Chun Kee Chung, Tae Hyun Park, Su Heon Woo, Sung-Jae Lee, Seung Heon Yang
Objective: In addition to bone bridging inside a cage or graft (intragraft bone bridging, InGBB), extragraft bone bridging (ExGBB) is commonly observed after anterior cervical discectomy and fusion (ACDF) with a stand-alone cage. However, solid bony fusion without the formation of ExGBB might be a desirable condition. We hypothesized that an insufficient contact area for InGBB might be a causative factor for ExGBB. The objective was to determine the minimal area of InGBB by finite element analysis...
November 2017: Journal of Korean Neurosurgical Society
https://www.readbyqxmd.com/read/29142232/tdp-43-misexpression-causes-defects-in-dendritic-growth
#5
Josiah J Herzog, Mugdha Deshpande, Leah Shapiro, Avital A Rodal, Suzanne Paradis
Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) share overlapping genetic causes and disease symptoms, and are linked neuropathologically by the RNA binding protein TDP-43 (TAR DNA binding protein-43 kDa). TDP-43 regulates RNA metabolism, trafficking, and localization of thousands of target genes. However, the cellular and molecular mechanisms by which dysfunction of TDP-43 contributes to disease pathogenesis and progression remain unclear. Severe changes in the structure of neuronal dendritic arbors disrupt proper circuit connectivity, which in turn could contribute to neurodegenerative disease...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29142056/familiarity-with-a-vocal-category-biases-the-compartmental-expression-of-arc-arg3-1-in-core-auditory-cortex
#6
Tamara N Ivanova, Christina Gross, Rudolph C Mappus, Yong Jun Kwon, Gary J Bassell, Robert C Liu
Learning to recognize a stimulus category requires experience with its many natural variations. However, the mechanisms that allow a category's sensorineural representation to be updated after experiencing new exemplars are not well understood, particularly at the molecular level. Here we investigate how a natural vocal category induces expression in the auditory system of a key synaptic plasticity effector immediate early gene, Arc/Arg3.1, which is required for memory consolidation. We use the ultrasonic communication system between mouse pups and adult females to study whether prior familiarity with pup vocalizations alters how Arc is engaged in the core auditory cortex after playback of novel exemplars from the pup vocal category...
December 2017: Learning & Memory
https://www.readbyqxmd.com/read/29141232/foxp1-promotes-embryonic-neural-stem-cell-differentiation-by-repressing-jagged1-expression
#7
Luca Braccioli, Stephin J Vervoort, Youri Adolfs, Cobi J Heijnen, Onur Basak, R Jeroen Pasterkamp, Cora H Nijboer, Paul J Coffer
Mutations in FOXP1 have been linked to neurodevelopmental disorders including intellectual disability and autism; however, the underlying molecular mechanisms remain ill-defined. Here, we demonstrate with RNA and chromatin immunoprecipitation sequencing that FOXP1 directly regulates genes controlling neurogenesis. We show that FOXP1 is expressed in embryonic neural stem cells (NSCs), and modulation of FOXP1 expression affects both neuron and astrocyte differentiation. Using a murine model of cortical development, FOXP1-knockdown in utero was found to reduce NSC differentiation and migration during corticogenesis...
November 14, 2017: Stem Cell Reports
https://www.readbyqxmd.com/read/29139130/less-cortical-thickness-in-patients-with-persistent-post-traumatic-headache-compared-with-healthy-controls-an-mri-study
#8
Catherine D Chong, Visar Berisha, Chia-Chun Chiang, Katherine Ross, Todd J Schwedt
OBJECTIVE: To investigate differences in cortical thickness in patients with persistent post-traumatic headache (PPTH) relative to healthy controls and to interrogate whether cortical morphology relates to headache burden (headache frequency, years with post-traumatic headache, PTH) in patients with PPTH. BACKGROUND: PTHs are one of the most common symptoms following concussion. In some patients, PTHs continue for longer than three months and are classified as PPTH...
November 15, 2017: Headache
https://www.readbyqxmd.com/read/29139050/modeling-mesoscopic-cortical-dynamics-using-a-mean-field-model-of-conductance-based-networks-of-adaptive-exponential-integrate-and-fire-neurons
#9
Yann Zerlaut, Sandrine Chemla, Frederic Chavane, Alain Destexhe
Voltage-sensitive dye imaging (VSDi) has revealed fundamental properties of neocortical processing at macroscopic scales. Since for each pixel VSDi signals report the average membrane potential over hundreds of neurons, it seems natural to use a mean-field formalism to model such signals. Here, we present a mean-field model of networks of Adaptive Exponential (AdEx) integrate-and-fire neurons, with conductance-based synaptic interactions. We study a network of regular-spiking (RS) excitatory neurons and fast-spiking (FS) inhibitory neurons...
November 15, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/29139049/feedforward-architectures-driven-by-inhibitory-interactions
#10
Yazan N Billeh, Michael T Schaub
Directed information transmission is paramount for many social, physical, and biological systems. For neural systems, scientists have studied this problem under the paradigm of feedforward networks for decades. In most models of feedforward networks, activity is exclusively driven by excitatory neurons and the wiring patterns between them, while inhibitory neurons play only a stabilizing role for the network dynamics. Motivated by recent experimental discoveries of hippocampal circuitry, cortical circuitry, and the diversity of inhibitory neurons throughout the brain, here we illustrate that one can construct such networks even if the connectivity between the excitatory units in the system remains random...
November 14, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/29138753/lesion-pattern-mechanisms-and-long-term-prognosis-in-patients-with-monoparetic-stroke-a-comparison-with-nonmonoparetic-stroke
#11
Seung-Jae Lee, Dong-Geun Lee, Hye-Jin Moon, Tae-Kyeong Lee
Background: Monoparetic stroke is rare but could be misdiagnosed as peripheral neuropathy. We investigated the prevalence, lesion pattern, stroke mechanism, and long-term prognosis in patients with monoparetic stroke. Methods: 586 acute ischemic stroke patients (including 31 with monoparesis) were studied. Monoparetic stroke was defined as a motor deficit in either an arm or a leg but without facial weakness or speech disturbance. Median follow-up period was 32...
2017: BioMed Research International
https://www.readbyqxmd.com/read/29138699/for-better-or-worse-the-effect-of-prismatic-adaptation-on-auditory-neglect
#12
Isabel Tissieres, Mona Elamly, Stephanie Clarke, Sonia Crottaz-Herbette
Patients with auditory neglect attend less to auditory stimuli on their left and/or make systematic directional errors when indicating sound positions. Rightward prismatic adaptation (R-PA) was repeatedly shown to alleviate symptoms of visuospatial neglect and once to restore partially spatial bias in dichotic listening. It is currently unknown whether R-PA affects only this ear-related symptom or also other aspects of auditory neglect. We have investigated the effect of R-PA on left ear extinction in dichotic listening, space-related inattention assessed by diotic listening, and directional errors in auditory localization in patients with auditory neglect...
2017: Neural Plasticity
https://www.readbyqxmd.com/read/29138458/low-intensity-pulsed-ultrasound-improves-behavioral-and-histological-outcomes-after-experimental-traumatic-brain-injury
#13
Wei-Shen Su, Chun-Hu Wu, Szu-Fu Chen, Feng-Yi Yang
The purpose of this study was to investigate the neuroprotective effects of low-intensity pulsed ultrasound (LIPUS) on behavioral and histological outcomes in a mouse model of traumatic brain injury (TBI). Mice subjected to controlled cortical impact injury were treated with LIPUS in the injured region daily for a period of 4 weeks. The effects of LIPUS on edema were observed by MR imaging in the mouse brain at 1 and 4 days following TBI. Brain water content, blood-brain barrier permeability, histology analysis, and behavioral studies were performed to assess the effects of LIPUS...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29137989/does-tms-on-v3-block-conscious-visual-perception
#14
Niina Salminen-Vaparanta, Mika Koivisto, Victor Vorobyev, Kati Alakurtti, Antti Revonsuo
Primary visual cortex (V1) and extrastriate V2 are necessary for the emergence of visual consciousness, but the effects of involvement of extrastriate V3 on visual consciousness is unclear. The objective of this study was to examine the causal role of V3 in visual consciousness in humans. We combined neuronavigated transcranial magnetic stimulation (TMS) with a computational model of the TMS-induced electric field to test whether or not the intact processing of visual input in V3, like in V1 and V2, is necessary for conscious visual perception...
November 11, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/29137726/mineralized-collagen-fibril-network-spatial-arrangement-influences-cortical-bone-fracture-behavior
#15
Yaohui Wang, Ani Ural
Bone is a hierarchical material exhibiting different fracture mechanisms at each length scale. At the submicroscale, the bone is composed of mineralized collagen fibrils (MCF). At this scale, the fracture processes in cortical bone have not been extensively studied in the literature. In this study, the influence of MCF size and orientation on the fracture behavior of bone under both transverse and longitudinal loading was investigated using novel 3D models of MCF networks with explicit representation of extra-fibrillar matrix...
November 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29137724/simplified-boundary-conditions-alter-cortical-trabecular-load-sharing-at-the-distal-radius-a-multiscale-finite-element-analysis
#16
Joshua E Johnson, Karen L Troy
High-resolution peripheral quantitative computed tomography (HR-pQCT) derived micro-finite element (FE) modeling is used to evaluate mechanical behavior at the distal radius microstructure. However, these analyses typically simulate non-physiologic simplified platen-compression boundary conditions on a small section of the distal radius. Cortical and trabecular regions contribute uniquely to distal radius mechanical behavior, and various factors affect these regions distinctly. Generalized strength predictions from standardized platen-compression analyses may not adequately capture region specific responses in bone...
November 4, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29136642/common-and-distinct-structural-features-of-schizophrenia-and-bipolar-disorder-the-european-network-on-psychosis-affective-disorders-and-cognitive-trajectory-enpact-study
#17
Eleonora Maggioni, Benedicto Crespo-Facorro, Igor Nenadic, Francesco Benedetti, Christian Gaser, Heinrich Sauer, Roberto Roiz-Santiañez, Sara Poletti, Veronica Marinelli, Marcella Bellani, Cinzia Perlini, Mirella Ruggeri, A Carlo Altamura, Vaibhav A Diwadkar, Paolo Brambilla
INTRODUCTION: Although schizophrenia (SCZ) and bipolar disorder (BD) share elements of pathology, their neural underpinnings are still under investigation. Here, structural Magnetic Resonance Imaging (MRI) data collected from a large sample of BD and SCZ patients and healthy controls (HC) were analyzed in terms of gray matter volume (GMV) using both voxel based morphometry (VBM) and a region of interest (ROI) approach. METHODS: The analysis was conducted on two datasets, Dataset1 (802 subjects: 243 SCZ, 176 BD, 383 HC) and Dataset2, a homogeneous subset of Dataset1 (301 subjects: 107 HC, 85 BD and 109 SCZ)...
2017: PloS One
https://www.readbyqxmd.com/read/29136119/the-bat-as-a-new-model-of-cortical-development
#18
Verónica Martínez-Cerdeño, Jasmin Camacho, Jeanelle Ariza, Hailee Rogers, Kayla Horton-Sparks, Anna Kreutz, Richard Behringer, John J Rasweiler, Stephen C Noctor
The organization of the mammalian cerebral cortex shares fundamental features across species. However, while the radial thickness of grey matter varies within one order of magnitude, the tangential spread of the cortical sheet varies by orders of magnitude across species. A broader sample of model species may provide additional clues for understanding mechanisms that drive cortical expansion. Here, we introduce the bat Carollia perspicillata as a new model species. The brain of C. perspicillata is similar in size to that of mouse but has a cortical neurogenic period at least 5 times longer than mouse, and nearly as long as that of the rhesus macaque, whose brain is 100 times larger...
November 9, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/29136105/same-genes-different-brains-neuroanatomical-differences-between-monozygotic-twins-discordant-for-musical-training
#19
Örjan de Manzano, Fredrik Ullén
Numerous cross-sectional and observational longitudinal studies show associations between expertise and regional brain anatomy. However, since these designs confound training with genetic predisposition, the causal role of training remains unclear. Here, we use a discordant monozygotic (identical) twin design to study expertise-dependent effects on neuroanatomy using musical training as model behavior, while essentially controlling for genetic factors and shared environment of upbringing. From a larger cohort of monozygotic twins, we were able to recruit 18 individuals (9 pairs) that were highly discordant for piano practice...
November 9, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/29135331/imaging-microglial-activation-and-amyloid-burden-in-amnestic-mild-cognitive-impairment
#20
Dunja Knezevic, Nicolaas Paul Lg Verhoeff, Sina Hafizi, Antonio P Strafella, Ariel Graff-Guerrero, Tarek Rajji, Bruce G Pollock, Sylvain Houle, Pablo M Rusjan, Romina Mizrahi
Amnestic mild cognitive impairment (aMCI) is defined as a transitional state between normal aging and Alzheimer's disease (AD). Given the replicated finding of increased microglial activation in AD, we sought to investigate whether microglial activation is also elevated in aMCI and whether it is related to amyloid beta (Aβ) burden in-vivo . Eleven aMCI participants and 14 healthy volunteers completed positron emission tomography (PET) scans with [(18)F]-FEPPA and [(11)C]-PIB. Given the known sensitivity in affinity of second-generation TSPO radioligands, participants were genotyped for the TSPO polymorphism and only high-affinity binders were included...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
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