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Synaptic scaling

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https://www.readbyqxmd.com/read/29328623/mimicking-biological-synaptic-functionality-with-an-indium-phosphide-synaptic-device-on-silicon-for-scalable-neuromorphic-computing
#1
Debarghya Sarkar, Jun Tao, Wei Wang, Qingfeng Lin, Matthew Yeung, Chenhao Ren, Rehan Kapadia
Neuromorphic or "brain-like" computation is a leading candidate for efficient, fault-tolerant processing of large-scale data, as well as real-time sensing and transduction of complex multivariate systems and networks such as self-driving vehicles or Internet of Things applications. In biology, the synapse serves as an active memory unit in the neural system, and is the component responsible for learning and memory. Electronically emulating this element via a compact, scalable technology which can be integrated in a 3-D architecture is critical for future implementations of neuromorphic processors...
January 12, 2018: ACS Nano
https://www.readbyqxmd.com/read/29312826/heteroassociative-storage-of-hippocampal-pattern-sequences-in-the-ca3-subregion
#2
Raphael Y de Camargo, Renan S Recio, Marcelo B Reyes
Background: Recent research suggests that the CA3 subregion of the hippocampus has properties of both autoassociative network, due to its ability to complete partial cues, tolerate noise, and store associations between memories, and heteroassociative one, due to its ability to store and retrieve sequences of patterns. Although there are several computational models of the CA3 as an autoassociative network, more detailed evaluations of its heteroassociative properties are missing. Methods: We developed a model of the CA3 subregion containing 10,000 integrate-and-fire neurons with both recurrent excitatory and inhibitory connections, and which exhibits coupled oscillations in the gamma and theta ranges...
2018: PeerJ
https://www.readbyqxmd.com/read/29301104/alzheimer-s-disease-from-firing-instability-to-homeostasis-network-collapse
#3
REVIEW
Samuel Frere, Inna Slutsky
Alzheimer's disease (AD) starts from pure cognitive impairments and gradually progresses into degeneration of specific brain circuits. Although numerous factors initiating AD have been extensively studied, the common principles underlying the transition from cognitive deficits to neuronal loss remain unknown. Here we describe an evolutionarily conserved, integrated homeostatic network (IHN) that enables functional stability of central neural circuits and safeguards from neurodegeneration. We identify the critical modules comprising the IHN and propose a central role of neural firing in controlling the complex homeostatic network at different spatial scales...
January 3, 2018: Neuron
https://www.readbyqxmd.com/read/29300903/multicontact-co-operativity-in-spike-timing-dependent-structural-plasticity-stabilizes-networks
#4
Moritz Deger, Alexander Seeholzer, Wulfram Gerstner
Excitatory synaptic connections in the adult neocortex consist of multiple synaptic contacts, almost exclusively formed on dendritic spines. Changes of spine volume, a correlate of synaptic strength, can be tracked in vivo for weeks. Here, we present a combined model of structural and spike-timing-dependent plasticity that explains the multicontact configuration of synapses in adult neocortical networks under steady-state and lesion-induced conditions. Our plasticity rule with Hebbian and anti-Hebbian terms stabilizes both the postsynaptic firing rate and correlations between the pre- and postsynaptic activity at an active synaptic contact...
December 28, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/29288874/modeling-spike-wave-discharges-by-a-complex-network-of-neuronal-oscillators
#5
Tatiana M Medvedeva, Marina V Sysoeva, Gilles van Luijtelaar, Ilya V Sysoev
PURPOSE: The organization of neural networks and the mechanisms, which generate the highly stereotypical for absence epilepsy spike-wave discharges (SWDs) is heavily debated. Here we describe such a model which can both reproduce the characteristics of SWDs and dynamics of coupling between brain regions, relying mainly on properties of hierarchically organized networks of a large number of neuronal oscillators. MODEL: We used a two level mesoscale model. The first level consists of three structures: the nervus trigeminus serving as an input, the thalamus and the somatosensory cortex; the second level of a group of nearby situated neurons belonging to one of three modeled structures...
December 13, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/29287081/firing-rate-equations-require-a-spike-synchrony-mechanism-to-correctly-describe-fast-oscillations-in-inhibitory-networks
#6
Federico Devalle, Alex Roxin, Ernest Montbrió
Recurrently coupled networks of inhibitory neurons robustly generate oscillations in the gamma band. Nonetheless, the corresponding Wilson-Cowan type firing rate equation for such an inhibitory population does not generate such oscillations without an explicit time delay. We show that this discrepancy is due to a voltage-dependent spike-synchronization mechanism inherent in networks of spiking neurons which is not captured by standard firing rate equations. Here we investigate an exact low-dimensional description for a network of heterogeneous canonical Class 1 inhibitory neurons which includes the sub-threshold dynamics crucial for generating synchronous states...
December 29, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/29284749/visualizing-long-term-single-molecule-dynamics-in-vivo-by-stochastic-protein-labeling
#7
Hui Liu, Peng Dong, Maria S Ioannou, Li Li, Jamien Shea, H Amalia Pasolli, Jonathan B Grimm, Patricia K Rivlin, Luke D Lavis, Minoru Koyama, Zhe Liu
Our ability to unambiguously image and track individual molecules in live cells is limited by packing of multiple copies of labeled molecules within the resolution limit. Here we devise a universal genetic strategy to precisely control copy number of fluorescently labeled molecules in a cell. This system has a dynamic range of ∼10,000-fold, enabling sparse labeling of proteins expressed at different abundance levels. Combined with photostable labels, this system extends the duration of automated single-molecule tracking by two orders of magnitude...
December 28, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29283020/gaba-from-inhibition-to-cognition-emerging-concepts
#8
T Schmidt-Wilcke, E Fuchs, K Funke, A Vlachos, F Müller-Dahlhaus, N A J Puts, R E Harris, R A E Edden
Neural functioning and plasticity can be studied on different levels of organization and complexity ranging from the molecular and synaptic level to neural circuitry of whole brain networks. Across neuroscience different methods are being applied to better understand the role of various neurotransmitter systems in the evolution of perception and cognition. GABA is the main inhibitory neurotransmitter in the adult mammalian brain and, depending on the brain region, up to 25% of the total number of cortical neurons are GABAergic interneurons...
October 1, 2017: Neuroscientist: a Review Journal Bringing Neurobiology, Neurology and Psychiatry
https://www.readbyqxmd.com/read/29278685/brain-plasticity-and-sleep-implication-for-movement-disorders
#9
REVIEW
Serena Caverzasio, Ninfa Amato, Mauro Manconi, Chiara Prosperetti, Alain Kaelin-Lang, William Duncan Hutchison, Salvatore Galati
Brain plasticity is a lifelong process and involves both Hebbian and non-Hebbian synaptic plasticity. The latter, such as intrinsic plasticity and homeostatic synaptic plasticity or synaptic scaling, is thought to counteract Hebbian plasticity, in order to maintain a balanced network. Recent studies support the role of sleep in the regulation of homeostatic synaptic plasticity involved in memory and learning processes. Most evidence focus on the dependence of memory and plasticity in sleep mechanisms. Abnormal brain plasticity during sleep might be implicated in the development of movement disorders, particularly Parkinson's disease (PD) and dystonia...
December 23, 2017: Neuroscience and Biobehavioral Reviews
https://www.readbyqxmd.com/read/29276477/cholinergic-modulation-of-cortical-microcircuits-is-layer-specific-evidence-from-rodent-monkey-and-human-brain
#10
REVIEW
Joshua Obermayer, Matthijs B Verhoog, Antonio Luchicchi, Huibert D Mansvelder
Acetylcholine (ACh) signaling shapes neuronal circuit development and underlies specific aspects of cognitive functions and behaviors, including attention, learning, memory and motivation. During behavior, activation of muscarinic and nicotinic acetylcholine receptors (mAChRs and nAChRs) by ACh alters the activation state of neurons, and neuronal circuits most likely process information differently with elevated levels of ACh. In several brain regions, ACh has been shown to alter synaptic strength as well. By changing the rules for synaptic plasticity, ACh can have prolonged effects on and rearrange connectivity between neurons that outlasts its presence...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/29250595/comparison-of-nmda-and-ampa-channel-expression-and-function-between-embryonic-and-adult-neurons-utilizing-microelectrode-array-systems
#11
Darin Edwards, Frank Sommerhage, Bonnie Berry, Hanna Nummer, Martina Raquet, Brad Clymer, Maria Stancescu, James J Hickman
Microelectrode arrays (MEAs) are innovative tools used to perform electrophysiological experiments for the study of electrical activity and connectivity in populations of neurons from dissociated cultures. Reliance upon neurons derived from embryonic tissue is a common limitation of neuronal/MEA hybrid systems and perhaps of neuroscience research in general, and the use of adult neurons could model fully functional in vivo parameters more closely. Spontaneous network activity was concurrently recorded from both embryonic and adult rat neurons cultured on MEAs for up to 10 weeks in vitro to characterize the synaptic connections between cell types...
December 11, 2017: ACS Biomaterials Science & Engineering
https://www.readbyqxmd.com/read/29247774/regulation-of-microglia-identity-from-an-epigenetic-and-transcriptomic-point-of-view
#12
Bart Jl Eggen, Erik Wgm Boddeke, Susanne M Kooistra
Microglia have long been recognized as the endogenous innate immune elements in the central nervous system (CNS) parenchyma. Besides fulfilling local immune related functions, they provide cross-talk between the CNS and the immune system at large. In the adult CNS, microglia are involved in maintaining brain homeostasis, modulating synaptic transmission and clearance of apoptotic cells. During embryonic development, microglia are responsible for the removal of supernumerary synapses and neurons, and neuronal network formation...
December 13, 2017: Neuroscience
https://www.readbyqxmd.com/read/29242504/scalable-excitatory-synaptic-circuit-design-using-floating-gate-based-leaky-integrators
#13
Vladimir Kornijcuk, Hyungkwang Lim, Inho Kim, Jong-Keuk Park, Wook-Seong Lee, Jung-Hae Choi, Byung Joon Choi, Doo Seok Jeong
We propose a scalable synaptic circuit realizing spike timing dependent plasticity (STDP)-compatible with randomly spiking neurons. The feasible working of the circuit was examined by circuit simulation using the BSIM 4.6.0 model. A distinguishable feature of the circuit is the use of floating-gate integrators that provide the compact implementation of biologically plausible relaxation time scale. This relaxation occurs on the basis of charge tunneling that mainly relies upon area-independent tunnel barrier properties (e...
December 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29241584/a-schizophrenia-linked-kalrn-coding-variant-alters-neuron-morphology-protein-function-and-transcript-stability
#14
Theron A Russell, Melanie J Grubisha, Christine L Remmers, Seok Kyu Kang, Marc P Forrest, Katharine R Smith, Katherine J Kopeikina, Ruoqi Gao, Robert A Sweet, Peter Penzes
BACKGROUND: Large-scale genetic studies have revealed that rare sequence variants, including single nucleotide variants (SNVs), in glutamatergic synaptic genes are enriched in schizophrenia patients. However, the majority are too rare to show any association with disease and have not been examined functionally. One such SNV, KALRN-P2255T, displays a penetrance that greatly exceeds that of previously identified schizophrenia-associated SNVs. Therefore, we sought to characterize its effects on the function of kalirin (Kal)-9, a dual Ras-related C3 botulinum toxin substrate 1 and Ras homologue gene family, member A (RhoA) guanine nucleotide exchange factor, upregulated in human schizophrenia brain tissue...
November 7, 2017: Biological Psychiatry
https://www.readbyqxmd.com/read/29236921/intermittent-theta-burst-transcranial-magnetic-stimulation-for-autism-spectrum-disorder-an-open-label-pilot-study
#15
Caio Abujadi, Paul E Croarkin, Bianca B Bellini, Helena Brentani, Marco A Marcolin
OBJECTIVE: Theta-burst stimulation (TBS) modulates synaptic plasticity more efficiently than standard repetitive transcranial magnetic stimulation delivery and may be a promising modality for neuropsychiatric disorders such as autism spectrum disorder (ASD). At present there are few effective interventions for prefrontal cortex dysfunction in ASD. We report on an open-label, pilot study of intermittent TBS (iTBS) to target executive function deficits and restricted, repetitive behaviors in male children and adolescents with ASD...
December 11, 2017: Revista Brasileira de Psiquiatria
https://www.readbyqxmd.com/read/29235396/brain-derived-neurotrophic-factor-bdnf-serum-level-in-women-with-first-episode-depression-correlation-with-clinical-and-metabolic-parameters
#16
Maria Skibinska, Pawel Kapelski, Aleksandra Rajewska-Rager, Joanna Pawlak, Aleksandra Szczepankiewicz, Beata Narozna, Joanna Twarowska-Hauser, Monika Dmitrzak-Weglarz
BACKGROUND: Brain-derived neurotrophic factor (BDNF) influences neuron differentiation during development, as well as the synaptic plasticity and neuron survival in adulthood. BDNF has been implicated in the pathogenesis of psychiatric disorders and its serum level is a potential biomarker for depression. The aim of this study was to examine serum levels of BDNF in first-episode depression and its correlation with clinical and metabolic parameters. MATERIALS AND METHODS: The study was performed on a group of 60 women: 30 diagnosed with a first-episode of depression and 30 healthy controls...
December 13, 2017: Nordic Journal of Psychiatry
https://www.readbyqxmd.com/read/29234064/homeostatic-plasticity-and-synaptic-scaling-in-the-adult-mouse-auditory-cortex
#17
Manuel Teichert, Lutz Liebmann, Christian A Hübner, Jürgen Bolz
It has been demonstrated that sensory deprivation results in homeostatic adjustments recovering neuronal activity of the deprived cortex. For example, deprived vision multiplicatively scales up mEPSC amplitudes in the primary visual cortex, commonly referred to as synaptic scaling. However, whether synaptic scaling also occurs in auditory cortex after auditory deprivation remains elusive. Using periodic intrinsic optical imaging in adult mice, we show that conductive hearing loss (CHL), initially led to a reduction of primary auditory cortex (A1) responsiveness to sounds...
December 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29230640/new-class-of-reduced-computationally-efficient-neuronal-models-for-large-scale-simulations-of-brain-dynamics
#18
Maxim Komarov, Giri Krishnan, Sylvain Chauvette, Nikolai Rulkov, Igor Timofeev, Maxim Bazhenov
During slow-wave sleep, brain electrical activity is dominated by the slow (< 1 Hz) electroencephalogram (EEG) oscillations characterized by the periodic transitions between active (or Up) and silent (or Down) states in the membrane voltage of the cortical and thalamic neurons. Sleep slow oscillation is believed to play critical role in consolidation of recent memories. Past computational studies, based on the Hodgkin-Huxley type neuronal models, revealed possible intracellular and network mechanisms of the neuronal activity during sleep, however, they failed to explore the large-scale cortical network dynamics depending on collective behavior in the large populations of neurons...
December 12, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/29230165/fear-conditioning-downregulates-rac1-activity-in-the-basolateral-amygdala-astrocytes-to-facilitate-the-formation-of-fear-memory
#19
Zhaohui Liao, Yezheng Tao, Xiaomu Guo, Deqin Cheng, Feifei Wang, Xing Liu, Lan Ma
Astrocytes are well known to scale synaptic structural and functional plasticity, while the role in learning and memory, such as conditioned fear memory, is poorly elucidated. Here, using pharmacological approach, we find that fluorocitrate (FC) significantly inhibits the acquisition of fear memory, suggesting that astrocyte activity is required for fear memory formation. We further demonstrate that fear conditioning downregulates astrocytic Rac1 activity in basolateral amygdala (BLA) in mice and promotes astrocyte structural plasticity...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/29228131/synaptic-potentiation-at-basal-and-apical-dendrites-of-hippocampal-pyramidal-neurons-involves-activation-of-a-distinct-set-of-extracellular-and-intracellular-molecular-cues
#20
Patrycja Brzdak, Olga Wójcicka, Monika Zareba-Koziol, Daniel Minge, Christian Henneberger, Jakub Wlodarczyk, Jerzy W Mozrzymas, Tomasz Wójtowicz
In the central nervous system, several forms of experience-dependent plasticity, learning and memory require the activity-dependent control of synaptic efficacy. Despite substantial progress in describing synaptic plasticity, mechanisms related to heterogeneity of synaptic functions at local circuits remain elusive. Here we studied the functional and molecular aspects of hippocampal circuit plasticity by analyzing excitatory synapses at basal and apical dendrites of mouse hippocampal pyramidal cells (CA1 region) in acute brain slices...
December 8, 2017: Cerebral Cortex
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