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Synaptic scaling

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https://www.readbyqxmd.com/read/28805794/large-scale-mapping-of-cortical-synaptic-projections-with-extracellular-electrode-arrays
#1
Mark Shein-Idelson, Lorenz Pammer, Mike Hemberger, Gilles Laurent
Understanding circuit computation in the nervous system requires sampling activity over large neural populations and maximizing the number of features that can be extracted. By combining planar arrays of extracellular electrodes with the three-layered cortex of turtles, we show that synaptic signals induced along individual axons as well as action potentials can be easily captured. Two types of information can be extracted from these signals, the neuronal subtype (inhibitory or excitatory)-whose identification is more reliable than with traditional measures such as action potential width-and a (partial) spatial map of functional axonal projections from individual neurons...
August 14, 2017: Nature Methods
https://www.readbyqxmd.com/read/28805336/matrix-stimulation-in-cancer-pain-methodology-safety-and-effectiveness
#2
M Mücke, M Tils, R Conrad, D Kravchenko, H Cuhls, L Radbruch, M Marinova, V Peuckmann-Post, R Rolke
BACKGROUND: This feasibility study addresses the applicability of matrix electrodes for the reduction of ongoing pain in cancer patients via low-frequency electrical stimulation (LFS). METHODS: Low-frequency matrix stimulation (4 Hz) was applied to the skin within the 'Head's zones' referring to the tumour localization of cancer pain patients. Pain at baseline was compared to a 3-day treatment interval consisting of 5 min of matrix stimulation in the morning and evening followed by a 3-day follow-up period without therapy...
August 14, 2017: European Journal of Pain: EJP
https://www.readbyqxmd.com/read/28804447/activity-dependent-arc-expression-and-homeostatic-synaptic-plasticity-are-altered-in-neurons-from-a-mouse-model-of-angelman-syndrome
#3
Elissa D Pastuzyn, Jason D Shepherd
Angelman syndrome (AS) is a neurodevelopmental disorder that results from deletions or mutations in chromosome 15, which usually includes the UBE3A gene. Ube3A protein is an E3 ubiquitin ligase that ubiquitinates proteins and targets them for degradation. The immediate-early gene Arc, a master regulator of synaptic plasticity, was identified as a putative substrate of Ube3A, but there have been conflicting reports on whether Arc is a bona fide E3 ligase substrate. Using multiple approaches, we found no evidence for a physical interaction between Arc and Ube3A in vivo...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28800327/analytical-strategy-to-prioritize-alzheimer-s-disease-candidate-genes-in-gene-regulatory-networks-using-public-expression-data
#4
Shweta Bagewadi Kawalia, Tamara Raschka, Mufassra Naz, Ricardo de Matos Simoes, Philipp Senger, Martin Hofmann-Apitius
Alzheimer's disease (AD) progressively destroys cognitive abilities in the aging population with tremendous effects on memory. Despite recent progress in understanding the underlying mechanisms, high drug attrition rates have put a question mark behind our knowledge about its etiology. Re-evaluation of past studies could help us to elucidate molecular-level details of this disease. Several methods to infer such networks exist, but most of them do not elaborate on context specificity and completeness of the generated networks, missing out on lesser-known candidates...
August 8, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28798324/calcium-imaging-revealed-no-modulatory-effect-on-odor-evoked-responses-of-the-drosophila-antennal-lobe-by-two-populations-of-inhibitory-local-interneurons
#5
Martin F Strube-Bloss, Veit Grabe, Bill S Hansson, Silke Sachse
Although we have considerable knowledge about how odors are represented in the antennal lobe (AL), the insects' analogue to the olfactory bulb, we still do not fully understand how the different neurons in the AL network contribute to the olfactory code. In Drosophila melanogaster we can selectively manipulate specific neuronal populations to elucidate their function in odor processing. Here we silenced the synaptic transmission of two distinct subpopulations of multiglomerular GABAergic local interneurons (LN1 and LN2) using shibire (shi (ts) ) and analyzed their impact on odor-induced glomerular activity at the AL input and output level...
August 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28782263/regulation-of-synaptic-scaling-by-action-potential-independent-miniature-neurotransmission
#6
REVIEW
Carlos Gonzalez-Islas, Pernille Bülow, Peter Wenner
Synaptic scaling represents a homeostatic adjustment in synaptic strength that was first identified as a cell-wide mechanism to achieve firing rate homeostasis after perturbations to spiking activity levels. In this review, we consider a form of synaptic scaling that is triggered by changes in action potential-independent neurotransmitter release. This plasticity appears to be both triggered and expressed locally at the dendritic site of the synapse that experiences a perturbation. A discussion of different forms of scaling triggered by different perturbations is presented...
August 7, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/28772946/influence-of-electrical-and-ionic-conductivities-of-organic-electronic-ion-pump-on-acetylcholine-exchange-performance
#7
Nazrin Abdullayeva, Mehmet Sankir
By using an easy and effective method of depositing conjugated polymers (PEDOT:PSS) on flexible substrates, a new design for organic bioelectronic devices has been developed. The purpose was to build up a system that mimics the motion of neurotransmitters in the synaptic cleft by obtaining an electrical to chemical signal transport. Fourier transform infrared (FTIR) spectroscopy and Raman measurements have demonstrated that electrochemical overoxidation region which separates the pristine PEDOT:PSS electrodes and allows ionic conduction has been achieved successfully...
May 26, 2017: Materials
https://www.readbyqxmd.com/read/28768764/src-homology-2-domain-containing-phosphotyrosine-phosphatase-2-shp2-controls-surface-glua1-in-synaptic-homeostasis
#8
Bin Zhang, Wen Lu
Src Homology 2 Domain Containing Phosphotyrosine Phosphatase 2 (Shp2) functions in synaptic plasticity, learning, and memory. However, the precise mechanisms by which this multifunctional protein contributes to synaptic function remains largely unknown. Homeostatic plasticity may be viewed as a process of bi-directional synaptic scaling, up or down. Through this process neuronal circuitry stability is maintained so that changes in synaptic strength may be preserved under changing conditions. Better understanding of these processes is needed...
August 2, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28759562/learning-and-executing-goal-directed-choices-by-internally-generated-sequences-in-spiking-neural-circuits
#9
John Palmer, Adam Keane, Pulin Gong
Recent neural ensemble recordings have established a link between goal-directed spatial decision making and internally generated neural sequences in the hippocampus of rats. To elucidate the synaptic mechanisms of these sequences underlying spatial decision making processes, we develop and investigate a spiking neural circuit model endowed with a combination of two synaptic plasticity mechanisms including spike-timing dependent plasticity (STDP) and synaptic scaling. In this model, the interplay of the combined synaptic plasticity mechanisms and network dynamics gives rise to neural sequences which propagate ahead of the animals' decision point to reach goal locations...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28757598/selective-serotonin-reuptake-inhibitors-for-treating-neurocognitive-and-neuropsychiatric-disorders-following-traumatic-brain-injury-an-evaluation-of-current-evidence
#10
REVIEW
John K Yue, John F Burke, Pavan S Upadhyayula, Ethan A Winkler, Hansen Deng, Caitlin K Robinson, Romain Pirracchio, Catherine G Suen, Sourabh Sharma, Adam R Ferguson, Laura B Ngwenya, Murray B Stein, Geoffrey T Manley, Phiroz E Tarapore
The prevalence of neuropsychiatric disorders following traumatic brain injury (TBI) is 20%-50%, and disorders of mood and cognition may remain even after recovery of neurologic function is achieved. Selective serotonin reuptake inhibitors (SSRI) block the reuptake of serotonin in presynaptic cells to lead to increased serotonergic activity in the synaptic cleft, constituting first-line treatment for a variety of neurocognitive and neuropsychiatric disorders. This review investigates the utility of SSRIs in treating post-TBI disorders...
July 25, 2017: Brain Sciences
https://www.readbyqxmd.com/read/28756341/once-upon-a-slow-time-in-the-land-of-recurrent-neuronal-networks%C3%A2
#11
REVIEW
Chengcheng Huang, Brent Doiron
The brain must both react quickly to new inputs as well as store a memory of past activity. This requires biology that operates over a vast range of time scales. Fast time scales are determined by the kinetics of synaptic conductances and ionic channels; however, the mechanics of slow time scales are more complicated. In this opinion article we review two distinct network-based mechanisms that impart slow time scales in recurrently coupled neuronal networks. The first is in strongly coupled networks where the time scale of the internally generated fluctuations diverges at the transition between stable and chaotic firing rate activity...
July 27, 2017: Current Opinion in Neurobiology
https://www.readbyqxmd.com/read/28754176/genome-wide-gene-by-lead-exposure-interaction-analysis-identifies-unc5d-as-a-candidate-gene-for-neurodevelopment
#12
Zhaoxi Wang, Birgit Claus Henn, Chaolong Wang, Yongyue Wei, Li Su, Ryan Sun, Han Chen, Peter J Wagner, Quan Lu, Xihong Lin, Robert Wright, David Bellinger, Molly Kile, Maitreyi Mazumdar, Martha Maria Tellez-Rojo, Lourdes Schnaas, David C Christiani
BACKGROUND: Neurodevelopment is a complex process involving both genetic and environmental factors. Prenatal exposure to lead (Pb) has been associated with lower performance on neurodevelopmental tests. Adverse neurodevelopmental outcomes are more frequent and/or more severe when toxic exposures interact with genetic susceptibility. METHODS: To explore possible loci associated with increased susceptibility to prenatal Pb exposure, we performed a genome-wide gene-environment interaction study (GWIS) in young children from Mexico (n = 390) and Bangladesh (n = 497)...
July 28, 2017: Environmental Health: a Global Access Science Source
https://www.readbyqxmd.com/read/28753456/synaptic-damage-underlies-eeg-abnormalities-in-postanoxic-encephalopathy-a-computational-study
#13
B J Ruijter, J Hofmeijer, H G E Meijer, M J A M van Putten
OBJECTIVE: In postanoxic coma, EEG patterns indicate the severity of encephalopathy and typically evolve in time. We aim to improve the understanding of pathophysiological mechanisms underlying these EEG abnormalities. METHODS: We used a mean field model comprising excitatory and inhibitory neurons, local synaptic connections, and input from thalamic afferents. Anoxic damage is modeled as aggravated short-term synaptic depression, with gradual recovery over many hours...
July 8, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28714852/the-small-molecule-mimetic-agonist-trimebutine-of-adhesion-molecule-l1-contributes-to-functional-recovery-after-spinal-cord-injury-in-mice
#14
Junping Xu, Chengliang Hu, Qiong Jiang, Hongchao Pan, Huifan Shen, Melitta Schachner
Curing spinal cord injury (SCI) in mammals is a daunting task because of the lack of permissive mechanisms and strong inhibitory responses at and around the lesion. The neural cell adhesion molecule L1CAM (L1) has been shown to favor axonal regrowth and enhance neuronal survival and synaptic plasticity, and thus constitutes a viable target to promote regeneration after SCI. Since delivery of full-length L1 or its extracellular domain could encounter difficulties in translation to therapy in humans, we have identified several small organic compounds that bind to L1 and stimulate neuronal survival, neuronal migration, and neurite outgrowth in an L1-dependent manner...
July 14, 2017: Disease Models & Mechanisms
https://www.readbyqxmd.com/read/28708060/synem-automated-synapse-detection-for-connectomics
#15
Benedikt Staffler, Manuel Berning, Kevin M Boergens, Anjali Gour, Patrick van der Smagt, Moritz Helmstaedter
Nerve tissue contains a high density of chemical synapses, about 1 per µm(3) in the mammalian cerebral cortex. Thus, even for small blocks of nerve tissue, dense connectomic mapping requires the identification of millions to billions of synapses. While the focus of connectomic data analysis has been on neurite reconstruction, synapse detection becomes limiting when datasets grow in size and dense mapping is required. Here, we report SynEM, a method for automated detection of synapses from conventionally en-bloc stained 3D electron microscopy image stacks...
July 14, 2017: ELife
https://www.readbyqxmd.com/read/28706303/memristive-neural-network-for-on-line-learning-and-tracking-with-brain-inspired-spike-timing-dependent-plasticity
#16
G Pedretti, V Milo, S Ambrogio, R Carboni, S Bianchi, A Calderoni, N Ramaswamy, A S Spinelli, D Ielmini
Brain-inspired computation can revolutionize information technology by introducing machines capable of recognizing patterns (images, speech, video) and interacting with the external world in a cognitive, humanlike way. Achieving this goal requires first to gain a detailed understanding of the brain operation, and second to identify a scalable microelectronic technology capable of reproducing some of the inherent functions of the human brain, such as the high synaptic connectivity (~10(4)) and the peculiar time-dependent synaptic plasticity...
July 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28704399/cooperative-stochastic-binding-and-unbinding-explain-synaptic-size-dynamics-and-statistics
#17
Aseel Shomar, Lukas Geyrhofer, Noam E Ziv, Naama Brenner
Synapses are dynamic molecular assemblies whose sizes fluctuate significantly over time-scales of hours and days. In the current study, we examined the possibility that the spontaneous microscopic dynamics exhibited by synaptic molecules can explain the macroscopic size fluctuations of individual synapses and the statistical properties of synaptic populations. We present a mesoscopic model, which ties the two levels. Its basic premise is that synaptic size fluctuations reflect cooperative assimilation and removal of molecules at a patch of postsynaptic membrane...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28694016/-18-f-fdopa-positron-emission-tomography-in-manganese-exposed-workers
#18
Susan R Criswell, Susan Searles Nielsen, Mark Warden, Joel S Perlmutter, Stephen M Moerlein, Hubert P Flores, John Huang, Lianne Sheppard, Noah Seixas, Harvey Checkoway, Brad A Racette
Occupational manganese (Mn) exposure is associated with the development of parkinsonism; however, the mechanism of neurotoxicity is unknown. Brain positron emission tomography (PET) imaging provides a non-invasive method of assessing dopamineric neuronal function. 6-[(18)F]fluoro-L-DOPA (FDOPA) PET reflects in-vivo nigrostriatal function, but results in Mn exposure are conflicting. The objective of this study was to investigate the association between Mn exposure secondary to occupational welding, FDOPA striatal uptake, and clinical parkinsonism as measured by Unified Parkinson Disease Rating Scale motor subscore 3 (UPDRS3) scores...
July 8, 2017: Neurotoxicology
https://www.readbyqxmd.com/read/28692643/inverse-stochastic-resonance-in-networks-of-spiking-neurons
#19
Muhammet Uzuntarla, Ernest Barreto, Joaquin J Torres
Inverse Stochastic Resonance (ISR) is a phenomenon in which the average spiking rate of a neuron exhibits a minimum with respect to noise. ISR has been studied in individual neurons, but here, we investigate ISR in scale-free networks, where the average spiking rate is calculated over the neuronal population. We use Hodgkin-Huxley model neurons with channel noise (i.e., stochastic gating variable dynamics), and the network connectivity is implemented via electrical or chemical connections (i.e., gap junctions or excitatory/inhibitory synapses)...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28691903/sequential-neuromodulation-of-hebbian-plasticity-offers-mechanism-for-effective-reward-based-navigation
#20
Zuzanna Brzosko, Sara Zannone, Wolfram Schultz, Claudia Clopath, Ole Paulsen
Spike timing-dependent plasticity (STDP) is under neuromodulatory control, which is correlated with distinct behavioral states. Previously, we reported that dopamine, a reward signal, broadens the time window for synaptic potentiation and modulates the outcome of hippocampal STDP even when applied after the plasticity induction protocol (Brzosko et al., 2015). Here, we demonstrate that sequential neuromodulation of STDP by acetylcholine and dopamine offers an efficacious model of reward-based navigation. Specifically, our experimental data in mouse hippocampal slices show that acetylcholine biases STDP toward synaptic depression, whilst subsequent application of dopamine converts this depression into potentiation...
July 10, 2017: ELife
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