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https://www.readbyqxmd.com/read/28527111/human-placenta-derived-mesenchymal-stem-cells-loaded-on-linear-ordered-collagen-scaffold-improves-functional-recovery-after-completely-transected-spinal-cord-injury-in-canine
#1
Sufang Han, Zhifeng Xiao, Xing Li, Huan Zhao, Bin Wang, Zhixue Qiu, Zhi Li, Xin Mei, Bai Xu, Caixia Fan, Bing Chen, Jin Han, Yanzheng Gu, Huilin Yang, Qin Shi, Jianwu Dai
Traumatic spinal cord injury (SCI) is a major challenge in the clinic. In this study, we sought to examine the synergistic effects of linear ordered collagen scaffold (LOCS) and human placenta-derived mesenchymal stem cells (hPMSCs) when transplanted into completely transected beagle dogs. After 36 weeks observation, we found that LOCS+hPMSCs implants promoted better hindlimb locomotor recovery than was observed in the non-treatment (control) group and LOCS group. Histological analysis showed that the regenerated tissue after treatment was well integrated with the host tissue, and dramatically reduced the volume of cystic and chondroitin sulfate proteoglycans (CSPGs) expression...
May 16, 2017: Science China. Life Sciences
https://www.readbyqxmd.com/read/28526325/expression-of-megf10-in-cholinergic-and-glutamatergic-neurons
#2
Yu Fujita, Tomoji Maeda, Koji Kamaishi, Rui Saito, Koyo Chiba, Xuefeng Shen, Kun Zou, Hiroto Komano
Multiple-EGF like domains 10 (MEGF10) is the mammalian homologue of Draper, a Drosophila phagocytosis receptor that plays an important role in synapse elimination and cell type-specific recognition. However, the expression and function of MEGF10 in the brain remain to be elucidated. Therefore, we aimed to clarify the regions and types of neurons that express MEGF10 in the brain, and to determine whether cells expressing MEGF10 possess phagocytic abilities. Our results indicated that MEGF10 is expressed in cholinergic and glutamatergic neurons of the cortex, hippocampus, and substantia nigra...
May 16, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28525811/an-online-supervised-learning-method-based-on-gradient-descent-for-spiking-neurons
#3
Yan Xu, Jing Yang, Shuiming Zhong
The purpose of supervised learning with temporal encoding for spiking neurons is to make the neurons emit a specific spike train encoded by precise firing times of spikes. The gradient-descent-based (GDB) learning methods are widely used and verified in the current research. Although the existing GDB multi-spike learning (or spike sequence learning) methods have good performance, they work in an offline manner and still have some limitations. This paper proposes an online GDB spike sequence learning method for spiking neurons that is based on the online adjustment mechanism of real biological neuron synapses...
April 27, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/28524815/anchoring-high-concentrations-of-syngap-at-postsynaptic-densities-via-liquid-liquid-phase-separation
#4
Menglong Zeng, Guanhua Bai, Mingjie Zhang
SynGAP, encoded by SYNGAP1, is a Ras/Rap GTPase activator specifically expressed in the nervous systems. SynGAP is one of the most abundant proteins in the postsynaptic densities (PSDs) of excitatory synapses and acts as a critical synaptic activity brake by tuning down synaptic GTPase activities. Mutations of SYNGAP1 have been frequently linked to brain disorders including intellectual disability, autisms, and seizure. SynGAP has been shown to undergo fast dispersions from synapses in response to stimulations, a strategy that neurons use to control the specific activities of the enzyme within the tiny, semi-open compartments in dendritic spines...
May 19, 2017: Small GTPases
https://www.readbyqxmd.com/read/28524267/synaptic-activity-suppresses-expression-of-neurogenic-differentiation-factor-2-in-an-nmda-receptor-dependent-manner
#5
Fading Chen, Benjamin J Hall
Neurogenic differentiation factor 2 (NeuroD2) is a highly expressed transcription factor in the developing central nervous system. In newborn neurons, NeuroD2-mediated gene expression promotes differentiation, maturation, and survival. In addition to these early, cell-intrinsic developmental processes, NeuroD2 in post-mitotic neurons also regulates synapse growth and ion channel expression to control excitability. While NeuroD2 transactivation can be induced in an activity-dependent manner, little is known about how expression of NeuroD2 itself is regulated...
May 19, 2017: Synapse
https://www.readbyqxmd.com/read/28523281/imaging-membrane-potential-changes-from-dendritic-spines-using-computer-generated-holography
#6
Dimitrii Tanese, Ju-Yun Weng, Valeria Zampini, Vincent De Sars, Marco Canepari, Balazs Rozsa, Valentina Emiliani, Dejan Zecevic
Electrical properties of neuronal processes are extraordinarily complex, dynamic, and, in the general case, impossible to predict in the absence of detailed measurements. To obtain such a measurement one would, ideally, like to be able to monitor electrical subthreshold events as they travel from synapses on distal dendrites and summate at particular locations to initiate action potentials. It is now possible to carry out these measurements at the scale of individual dendritic spines using voltage imaging. In these measurements, the voltage-sensitive probes can be thought of as transmembrane voltmeters with a linear scale, which directly monitor electrical signals...
July 2017: Neurophotonics
https://www.readbyqxmd.com/read/28522733/activation-of-perk-elicits-memory-impairment-through-inactivation-of-creb-and-downregulation-of-psd95-following-traumatic-brain-injury
#7
Tanusree Sen, Rajaneesh Gupta, Helen Kaiser, Nilkantha Sen
The PKR-like ER kinase (PERK) a transmembrane protein resides in the endoplasmic reticulum (ER) and activation of PERK serve as a key sensor of ER-stress which has been implicated in Traumatic Brain Injury (TBI). The loss of memory is one of the most common symptoms following TBI; however, the precise role of PERK activation in memory impairment after TBI has not been well elucidated. Here we have shown that blocking the activation of PERK using GSK2656157 prevents the loss of dendritic spines and rescues memory deficits following TBI...
May 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28522379/the-coding-question
#8
REVIEW
C R Gallistel
Recent electrophysiological results imply that the duration of the stimulus onset asynchrony in eyeblink conditioning is encoded by a mechanism intrinsic to the cerebellar Purkinje cell. This raises the general question - how is quantitative information (durations, distances, rates, probabilities, amounts, etc.) transmitted by spike trains and encoded into engrams? The usual assumption is that information is transmitted by firing rates. However, rate codes are energetically inefficient and computationally awkward...
May 15, 2017: Trends in Cognitive Sciences
https://www.readbyqxmd.com/read/28521778/cortical-kainate-receptors-and-behavioral-anxiety
#9
REVIEW
Min Zhuo
The study of glutamatergic synapses mainly focuses on the memory-related hippocampus. Recent studies in the cortical areas such as the anterior cingulate cortex (ACC) show that excitatory synapses can undergo long-term plastic changes in adult animals. Long-term potentiation (LTP) of cortical synapses may play important roles in chronic pain and anxiety. In addition to NMDA and AMPA receptors, kainate (KA) receptors have been found to play roles in synaptic transmission, regulation and presynaptic forms of LTP...
May 18, 2017: Molecular Brain
https://www.readbyqxmd.com/read/28521702/role-of-ectonucleotidases-in-the-synapse-formation-during-brain-development-physiological-and-pathological-implications
#10
Ivana Grković, Dunja Drakulić, Jelena Martinović, Nataša Mitrović
Extracellular adenine nucleotides and nucleosides, such as ATP and adenosine, are among the most recently identified and least investigated diffusible signaling factors that contribute to the structural and functional remodeling of the brain, both during embryonic and postnatal development. Their levels in the extracellular milieu are tightly controlled by various ectonucleotidases: ectonucleotide pyrophosphatase/phosphodiesterases (E-NPP), alkaline phosphatases (AP), ectonucleoside triphosphate diphosphohydrolases (E-NTPDases) and ecto-5'-nucleotidase (eN)...
May 18, 2017: Current Neuropharmacology
https://www.readbyqxmd.com/read/28521247/cognitive-performance-of-juvenile-monkeys-after-chronic-fluoxetine-treatment
#11
Mari S Golub, Edward P Hackett, Casey E Hogrefe, Csaba Leranth, John D Elsworth, Robert H Roth
Potential long term effects on brain development are a concern when drugs are used to treat depression and anxiety in childhood. In this study, male juvenile rhesus monkeys (three-four years of age) were dosed with fluoxetine or vehicle (N=16/group) for two years. Histomorphometric examination of cortical dendritic spines conducted after euthanasia at one year postdosing (N=8/group) suggested a trend toward greater dendritic spine synapse density in prefrontal cortex of the fluoxetine-treated monkeys. During dosing, subjects were trained for automated cognitive testing, and evaluated with a test of sustained attention...
May 1, 2017: Developmental Cognitive Neuroscience
https://www.readbyqxmd.com/read/28521135/synaptotagmin-7-mediated-asynchronous-release-boosts-high-fidelity-synchronous-transmission-at-a-central-synapse
#12
Fujun Luo, Thomas C Südhof
Synchronous release triggered by Ca(2+) binding to synaptotagmin-1, -2, or -9 is thought to drive fast synaptic transmission, whereas asynchronous release induced by Ca(2+) binding to synaptotagmin-7 is thought to produce delayed synaptic signaling, enabling prolonged synaptic computations. However, it is unknown whether synaptotagmin-7-dependent asynchronous release performs a physiological function at fast synapses lacking a prolonged signaling mode, such as the calyx of Held synapse. Here, we show at the calyx synapse that synaptotagmin-7-dependent asynchronous release indeed does not produce a prolonged synaptic signal after a stimulus train and does not contribute to short-term plasticity, but induces a steady-state, asynchronous postsynaptic current during stimulus trains...
May 17, 2017: Neuron
https://www.readbyqxmd.com/read/28521126/structural-and-functional-architecture-of-ampa-type-glutamate-receptors-and-their-auxiliary-proteins
#13
REVIEW
Ingo H Greger, Jake F Watson, Stuart G Cull-Candy
AMPA receptors (AMPARs) are tetrameric ion channels that together with other ionotropic glutamate receptors (iGluRs), the NMDA and kainate receptors, mediate a majority of excitatory neurotransmission in the central nervous system. Whereas NMDA receptors gate channels with slow kinetics, responsible primarily for generating long-term synaptic potentiation and depression, AMPARs are the main fast transduction elements at synapses and are critical for the expression of plasticity. The kinetic and conductance properties of AMPARs are laid down during their biogenesis and are regulated by post-transcriptional RNA editing, splice variation, post-translational modification, and subunit composition...
May 17, 2017: Neuron
https://www.readbyqxmd.com/read/28521120/synaptotagmins-that-s-why-so-many
#14
Chong Chen, Peter Jonas
Synaptotagmin 7 (Syt7) was originally identified as a slow Ca(2+) sensor for lysosome fusion, but its function at fast synapses is controversial. The paper by Luo and Südhof (2017) in this issue of Neuron shows that at the calyx of Held in the auditory brainstem Syt7 triggers asynchronous release during stimulus trains, resulting in reliable and temporally precise high-frequency transmission. Thus, a slow Ca(2+) sensor contributes to the fast signaling properties of the calyx synapse.
May 17, 2017: Neuron
https://www.readbyqxmd.com/read/28520784/presynaptic-a%C3%AE-40-prevents-synapse-addition-in-the-adult-drosophila-neuromuscular-junction
#15
Begoña López-Arias, Enrique Turiégano, Ignacio Monedero, Inmaculada Canal, Laura Torroja
Complexity in the processing of the Amyloid Precursor Protein, which generates a mixture of βamyloid peptides, lies beneath the difficulty in understanding the etiology of Alzheimer's disease. Moreover, whether Aβ peptides have any physiological role in neurons is an unresolved question. By expressing single, defined Aβ peptides in Drosophila, specific effects can be discriminated in vivo. Here, we show that in the adult neuromuscular junction (NMJ), presynaptic expression of Aβ40 hinders the synaptic addition that normally occurs in adults, yielding NMJs with an invariable number of active zones at all ages tested...
2017: PloS One
https://www.readbyqxmd.com/read/28520739/timing-dependent-ltp-and-ltd-in-mouse-primary-visual-cortex-following-different-visual-deprivation-models
#16
Yatu Guo, Wei Zhang, Xia Chen, Junhong Fu, Wenbo Cheng, Desheng Song, Xiaolei Qu, Zhuo Yang, Kanxing Zhao
Visual deprivation during the critical period induces long-lasting changes in cortical circuitry by adaptively modifying neuro-transmission and synaptic connectivity at synapses. Spike timing-dependent plasticity (STDP) is considered a strong candidate for experience-dependent changes. However, the visual deprivation forms that affect timing-dependent long-term potentiation(LTP) and long-term depression(LTD) remain unclear. Here, we demonstrated the temporal window changes of tLTP and tLTD, elicited by coincidental pre- and post-synaptic firing, following different modes of 6-day visual deprivation...
2017: PloS One
https://www.readbyqxmd.com/read/28518121/two-algorithms-for-high-throughput-and-multi-parametric-quantification-of-drosophila-neuromuscular-junction-morphology
#17
Anna Castells-Nobau, Bonnie Nijhof, Ilse Eidhof, Louis Wolf, Jolanda M Scheffer-de Gooyert, Ignacio Monedero, Laura Torroja, Jeroen A W M van der Laak, Annette Schenck
Synaptic morphology is tightly related to synaptic efficacy, and in many cases morphological synapse defects ultimately lead to synaptic malfunction. The Drosophila larval neuromuscular junction (NMJ), a well-established model for glutamatergic synapses, has been extensively studied for decades. Identification of mutations causing NMJ morphological defects revealed a repertoire of genes that regulate synapse development and function. Many of these were identified in large-scale studies that focused on qualitative approaches to detect morphological abnormalities of the Drosophila NMJ...
May 3, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28518110/external-excitation-of-neurons-using-electric-and-magnetic-fields-in-one-and-two-dimensional-cultures
#18
Shani Stern, Assaf Rotem, Yuri Burnishev, Eyal Weinreb, Elisha Moses
A neuron will fire an action potential when its membrane potential exceeds a certain threshold. In typical activity of the brain, this occurs as a result of chemical inputs to its synapses. However, neurons can also be excited by an imposed electric field. In particular, recent clinical applications activate neurons by creating an electric field externally. It is therefore of interest to investigate how the neuron responds to the external field and what causes the action potential. Fortunately, precise and controlled application of an external electric field is possible for embryonic neuronal cells that are excised, dissociated and grown in cultures...
May 7, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28518055/a-positive-feedback-loop-linking-enhanced-mglur-function-and-basal-calcium-in-spinocerebellar-ataxia-type-2
#19
Pratap Meera, Stefan Pulst, Thomas Otis
Metabotropic glutamate receptor 1 (mGluR1) function in Purkinje neurons (PNs) is essential for cerebellar development and for motor learning and altered mGluR1 signaling causes ataxia. Downstream of mGluR1, dysregulation of calcium homeostasis has been hypothesized as a key pathological event in genetic forms of ataxia but the underlying mechanisms remain unclear. We find in a spinocerebellar ataxia type 2 (SCA2) mouse model that calcium homeostasis in PNs is disturbed across a broad range of physiological conditions...
May 18, 2017: ELife
https://www.readbyqxmd.com/read/28516990/cross-talk-between-neurometals-and-amyloidogenic-proteins-at-the-synapse-and-the-pathogenesis-of-neurodegenerative-diseases
#20
REVIEW
M Kawahara, M Kato-Negishi, K Tanaka
Increasing evidence suggests that disruption of metal homeostasis contributes to the pathogenesis of various neurodegenerative diseases, including Alzheimer's disease, prion diseases, Lewy body diseases, and vascular dementia. Conformational changes of disease-related proteins (amyloidogenic proteins), such as β-amyloid protein, prion proteins, and α-synuclein, are well-established contributors to neurotoxicity and to the pathogenesis of these diseases. Recent studies have demonstrated that these amyloidogenic proteins are metalloproteins that bind trace elements, including zinc, iron, copper, and manganese, and play significant roles in the maintenance of metal homeostasis...
May 18, 2017: Metallomics: Integrated Biometal Science
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