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https://www.readbyqxmd.com/read/28432787/presynaptic-morphology-and-vesicular-composition-determine-vesicle-dynamics-in-mouse-central-synapses
#1
Laurent Guillaud, Dimitar Dimitrov, Tomoyuki Takahashi
Transport of synaptic vesicles (SVs) in nerve terminals is thought to play essential roles in maintenance of neurotransmission. To identify factors modulating SV movements, we performed real-time imaging analysis of fluorescently labeled SVs in giant calyceal and conventional hippocampal terminals. Compared with small hippocampal terminals, SV movements in giant calyceal terminals were faster, longer and kinetically more heterogeneous. Morphological maturation of giant calyceal terminals was associated with an overall reduction in SV mobility and displacement heterogeneity...
April 22, 2017: ELife
https://www.readbyqxmd.com/read/28432779/nmdar-independent-hippocampal-long-term-depression-impairment-after-status-epilepticus-in-a-lithium-pilocarpine-model-of-temporal-lobe-epilepsy
#2
Andrey D Ivanov, Aleksey V Zaitsev
Temporal lobe epilepsy is usually associated with cognitive decline and memory deficits. Despite numerous existing studies on various animal models, the mechanisms of these deficits remain largely unclear. A specific form of long-term synaptic efficacy changes - long-term depression (LTD) - is thought to play an important role in memory formation and learning. However, extremely little is known about the possible alteration of LTD induction and dynamics after a status epilepticus (SE). In the present work we investigated the acute and delayed effects of lithium-pilocarpine-induced SE on NMDAR-dependent and NMDAR-independent hippocampal LTD in vitro...
April 22, 2017: Synapse
https://www.readbyqxmd.com/read/28432423/note-on-the-coefficient-of-variations-of-neuronal-spike-trains
#3
Johannes Lengler, Angelika Steger
It is known that many neurons in the brain show spike trains with a coefficient of variation (CV) of the interspike times of approximately 1, thus resembling the properties of Poisson spike trains. Computational studies have been able to reproduce this phenomenon. However, the underlying models were too complex to be examined analytically. In this paper, we offer a simple model that shows the same effect but is accessible to an analytic treatment. The model is a random walk model with a reflecting barrier; we give explicit formulas for the CV in the regime of excess inhibition...
April 21, 2017: Biological Cybernetics
https://www.readbyqxmd.com/read/28432360/functional-ectopic-neuritogenesis-by-retinal-rod-bipolar-cells-is-regulated-by-mir-125b-5p-during-retinal-remodeling-in-rcs-rats
#4
Yan Fu, Baoke Hou, Chuanhuang Weng, Weiping Liu, Jiaman Dai, Congjian Zhao, Zheng Qin Yin
Following retinal degeneration, retinal remodeling can cause neuronal microcircuits to undergo structural alterations, which particularly affect the dendrites of bipolar cells. However, the mechanisms and functional consequences of such changes remain unclear. Here, we used Royal College of Surgeon (RCS) rats as a model of retinal degeneration, to study structural changes in rod bipolar cells (RBCs) and the underlying mechanisms of these changes. We found that, with retinal degeneration, RBC dendrites extended into the outer nuclear layer (ONL) of the retina, and the ectopic dendrites formed synapses with the remaining photoreceptors...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28432353/severe-hearing-loss-and-outer-hair-cell-death-in-homozygous-foxo3-knockout-mice-after-moderate-noise-exposure
#5
Felicia Gilels, Stephen T Paquette, Holly J Beaulac, Anwen Bullen, Patricia M White
Noise induced hearing loss (NIHL) is a disease that affects millions of Americans. Identifying genetic pathways that influence recovery from noise exposure is an important step forward in understanding NIHL. The transcription factor Foxo3 integrates the cellular response to oxidative stress and plays a role in extending lifespan in many organisms, including humans. Here we show that Foxo3 is required for auditory function after noise exposure in a mouse model system, measured by ABR. Absent Foxo3, outer hair cells are lost throughout the middle and higher frequencies...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28432141/the-spacing-effect-for-structural-synaptic-plasticity-provides-specificity-and-precision-in-plastic-changes
#6
Martin A San, L Rela, B D Gelb, M R Pagani
In contrast to trials of training without intervals (massed training), training trials spaced over time (spaced training) induce a more persistent memory identified as long-term memory (LTM). This phenomenon known as "the spacing effect for memory" is poorly understood. LTM is supported by structural synaptic plasticity; however, how synapses integrate spaced stimuli remains elusive. Here, we analyzed events of structural synaptic plasticity at the single synapse level after distinct patterns of stimulation in motoneurons of Drosophila We found that the spacing effect is a phenomenon detected at synaptic level, which determine the specificity and the precision in structural synaptic plasticity...
April 21, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28432017/dual-functional-nanoparticles-for-precise-drug-delivery-to-alzheimer-s-disease-lesions-targeting-mechanisms-pharmacodynamics-and-safety
#7
Xiaoyao Zheng, Chi Zhang, Qian Guo, Xu Wan, Xiayan Shao, Qingfeng Liu, Qizhi Zhang
Alzheimer's disease (AD) is the most common form of dementia and is characterized by the cerebral accumulation of extracellular amyloid plaques. In a previous study, this histopathological hallmark was used as a target on a dual-functional nanoparticle (TQNP) to deliver biotechnological drugs, such as the H102 peptide, a β-sheet breaker, to AD lesions precisely. This delivery system could reduce the amyloid-β (Aβ) burden in the brains of AD model mice, as well as ameliorated the memory impairment of the mice...
April 18, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28430358/regulation-of-axon-arborization-pattern-in-the-developing-chick-ciliary-ganglion-possible-involvement-of-caspase-3
#8
Hidetaka Katow, Teppei Kanaya, Tomohisa Ogawa, Ryo Egawa, Hiromu Yawo
During a certain critical period in the development of the central and peripheral nervous systems, axonal branches and synapses are massively reorganized to form mature connections. In this process, neurons search their appropriate targets, expanding and/or retracting their axons. Recent work suggested that the caspase superfamily regulates the axon morphology. Here, we tested the hypothesis that caspase 3, which is one of the major executioners in apoptotic cell death, is involved in regulating the axon arborization...
April 21, 2017: Development, Growth & Differentiation
https://www.readbyqxmd.com/read/28428560/combination-of-high-density-microelectrode-array-and-patch-clamp-recordings-to-enable-studies-of-multisynaptic-integration
#9
David Jäckel, Douglas J Bakkum, Thomas L Russell, Jan Müller, Milos Radivojevic, Urs Frey, Felix Franke, Andreas Hierlemann
We present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11'000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28426966/assembly-of-excitatory-synapses-in-the-absence-of-glutamatergic-neurotransmission
#10
Richard Sando, Eric Bushong, Yongchuan Zhu, Min Huang, Camille Considine, Sebastien Phan, Suyeon Ju, Marco Uytiepo, Mark Ellisman, Anton Maximov
Synaptic excitation mediates a broad spectrum of structural changes in neural circuits across the brain. Here, we examine the morphologies, wiring, and architectures of single synapses of projection neurons in the murine hippocampus that developed in virtually complete absence of vesicular glutamate release. While these neurons had smaller dendritic trees and/or formed fewer contacts in specific hippocampal subfields, their stereotyped connectivity was largely preserved. Furthermore, loss of release did not disrupt the morphogenesis of presynaptic terminals and dendritic spines, suggesting that glutamatergic neurotransmission is unnecessary for synapse assembly and maintenance...
April 19, 2017: Neuron
https://www.readbyqxmd.com/read/28426965/formation-and-maintenance-of-functional-spines-in-the-absence-of-presynaptic-glutamate-release
#11
Albrecht Sigler, Won Chan Oh, Cordelia Imig, Bekir Altas, Hiroshi Kawabe, Benjamin H Cooper, Hyung-Bae Kwon, Jeong-Seop Rhee, Nils Brose
Dendritic spines are the major transmitter reception compartments of glutamatergic synapses in most principal neurons of the mammalian brain and play a key role in the function of nerve cell circuits. The formation of functional spine synapses is thought to be critically dependent on presynaptic glutamatergic signaling. By analyzing CA1 pyramidal neurons in mutant hippocampal slice cultures that are essentially devoid of presynaptic transmitter release, we demonstrate that the formation and maintenance of dendrites and functional spines are independent of synaptic glutamate release...
April 19, 2017: Neuron
https://www.readbyqxmd.com/read/28425471/nonspecific-synaptic-plasticity-improves-the-recognition-of-sparse-patterns-degraded-by-local-noise
#12
Karen Safaryan, Reinoud Maex, Neil Davey, Rod Adams, Volker Steuber
Many forms of synaptic plasticity require the local production of volatile or rapidly diffusing substances such as nitric oxide. The nonspecific plasticity these neuromodulators may induce at neighboring non-active synapses is thought to be detrimental for the specificity of memory storage. We show here that memory retrieval may benefit from this non-specific plasticity when the applied sparse binary input patterns are degraded by local noise. Simulations of a biophysically realistic model of a cerebellar Purkinje cell in a pattern recognition task show that, in the absence of noise, leakage of plasticity to adjacent synapses degrades the recognition of sparse static patterns...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28424655/sustained-and-transient-vestibular-systems-a-physiological-basis-for-interpreting-vestibular-function
#13
REVIEW
Ian S Curthoys, Hamish G MacDougall, Pierre-Paul Vidal, Catherine de Waele
Otolithic afferents with regular resting discharge respond to gravity or low-frequency linear accelerations, and we term these the static or sustained otolithic system. However, in the otolithic sense organs, there is anatomical differentiation across the maculae and corresponding physiological differentiation. A specialized band of receptors called the striola consists of mainly type I receptors whose hair bundles are weakly tethered to the overlying otolithic membrane. The afferent neurons, which form calyx synapses on type I striolar receptors, have irregular resting discharge and have low thresholds to high frequency (e...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28424606/bifurcation-analysis-on-phase-amplitude-cross-frequency-coupling-in-neural-networks-with-dynamic-synapses
#14
Takumi Sase, Yuichi Katori, Motomasa Komuro, Kazuyuki Aihara
We investigate a discrete-time network model composed of excitatory and inhibitory neurons and dynamic synapses with the aim at revealing dynamical properties behind oscillatory phenomena possibly related to brain functions. We use a stochastic neural network model to derive the corresponding macroscopic mean field dynamics, and subsequently analyze the dynamical properties of the network. In addition to slow and fast oscillations arising from excitatory and inhibitory networks, respectively, we show that the interaction between these two networks generates phase-amplitude cross-frequency coupling (CFC), in which multiple different frequency components coexist and the amplitude of the fast oscillation is modulated by the phase of the slow oscillation...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28424589/the-calcium-channel-c-terminal-and-synaptic-vesicle-tethering-analysis-by-immuno-nanogold-localization
#15
Robert H C Chen, Qi Li, Christine A Snidal, Sabiha R Gardezi, Elise F Stanley
At chemical synapses the incoming action potential triggers the influx of Ca(2+) through voltage-sensitive calcium channels (CaVs, typically CaV2.1 and 2.2) and the ions binds to sensors associated with docked, transmitter filled synaptic vesicles (SVs), triggering their fusion and discharge. The CaVs and docked SVs are located within the active zone (AZ) region of the synapse which faces a corresponding neurotransmitter receptor-rich region on the post-synaptic cell. Evidence that the fusion of a SV can be gated by Ca(2+) influx through a single CaV suggests that the channel and docked vesicle are linked by one or more molecular tethers (Stanley, 1993)...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28424586/app-protein-family-signaling-at-the-synapse-insights-from-intracellular-app-binding-proteins
#16
REVIEW
Suzanne Guénette, Paul Strecker, Stefan Kins
Understanding the molecular mechanisms underlying amyloid precursor protein family (APP/APP-like proteins, APLP) function in the nervous system can be achieved by studying the APP/APLP interactome. In this review article, we focused on intracellular APP interacting proteins that bind the YENPTY internalization motif located in the last 15 amino acids of the C-terminal region. These proteins, which include X11/Munc-18-interacting proteins (Mints) and FE65/FE65Ls, represent APP cytosolic binding partners exhibiting different neuronal functions...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28424512/human-umbilical-cord-plasma-proteins-revitalize-hippocampal-function-in-aged-mice
#17
Joseph M Castellano, Kira I Mosher, Rachelle J Abbey, Alisha A McBride, Michelle L James, Daniela Berdnik, Jadon C Shen, Bende Zou, Xinmin S Xie, Martha Tingle, Izumi V Hinkson, Martin S Angst, Tony Wyss-Coray
Ageing drives changes in neuronal and cognitive function, the decline of which is a major feature of many neurological disorders. The hippocampus, a brain region subserving roles of spatial and episodic memory and learning, is sensitive to the detrimental effects of ageing at morphological and molecular levels. With advancing age, synapses in various hippocampal subfields exhibit impaired long-term potentiation, an electrophysiological correlate of learning and memory. At the molecular level, immediate early genes are among the synaptic plasticity genes that are both induced by long-term potentiation and downregulated in the aged brain...
April 19, 2017: Nature
https://www.readbyqxmd.com/read/28424476/neurons-export-extracellular-vesicles-enriched-in-cysteine-string-protein-and-misfolded-protein-cargo
#18
Jingti Deng, Carolina Koutras, Julien Donnelier, Mana Alshehri, Maryam Fotouhi, Martine Girard, Steve Casha, Peter S McPherson, Stephen M Robbins, Janice E A Braun
The fidelity of synaptic transmission depends on the integrity of the protein machinery at the synapse. Unfolded synaptic proteins undergo refolding or degradation in order to maintain synaptic proteostasis and preserve synaptic function, and buildup of unfolded/toxic proteins leads to neuronal dysfunction. Many molecular chaperones contribute to proteostasis, but one in particular, cysteine string protein (CSPα), is critical for proteostasis at the synapse. In this study we report that exported vesicles from neurons contain CSPα...
April 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28424166/applying-fluid-biomarkers-to-alzheimer-s-disease
#19
Henrik Zetterberg
Alzheimer's disease (AD) is a common neurodegenerative disease that starts with a clinically silent phase of a decade or more during which brain pathologies accumulate predominantly in the medial temporal lobe but also elsewhere in the brain. Network dysfunction and clinical symptoms typically appear when senile plaque (amyloid β) and neurofibrillary tangle (tau) pathologies meet in the brain parenchyma, producing synapse and neuronal loss. For plaque and tangle pathologies, reliable fluid biomarkers have been developed...
April 19, 2017: American Journal of Physiology. Cell Physiology
https://www.readbyqxmd.com/read/28422957/towards-a-theory-of-cortical-columns-from-spiking-neurons-to-interacting-neural-populations-of-finite-size
#20
Tilo Schwalger, Moritz Deger, Wulfram Gerstner
Neural population equations such as neural mass or field models are widely used to study brain activity on a large scale. However, the relation of these models to the properties of single neurons is unclear. Here we derive an equation for several interacting populations at the mesoscopic scale starting from a microscopic model of randomly connected generalized integrate-and-fire neuron models. Each population consists of 50-2000 neurons of the same type but different populations account for different neuron types...
April 19, 2017: PLoS Computational Biology
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