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Synaptic scaling

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https://www.readbyqxmd.com/read/27917111/scale-invariant-disordered-nanotopography-promotes-hippocampal-neuron-development-and-maturation-with-involvement-of-mechanotransductive-pathways
#1
Carsten Schulte, Maddalena Ripamonti, Elisa Maffioli, Martino A Cappelluti, Simona Nonnis, Luca Puricelli, Jacopo Lamanna, Claudio Piazzoni, Alessandro Podestà, Cristina Lenardi, Gabriella Tedeschi, Antonio Malgaroli, Paolo Milani
The identification of biomaterials which promote neuronal maturation up to the generation of integrated neural circuits is fundamental for modern neuroscience. The development of neural circuits arises from complex maturative processes regulated by poorly understood signaling events, often guided by the extracellular matrix (ECM). Here we report that nanostructured zirconia surfaces, produced by supersonic cluster beam deposition of zirconia nanoparticles and characterized by ECM-like nanotopographical features, can direct the maturation of neural networks...
2016: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/27915209/development-of-neural-population-activity-towards-self-organized-criticality
#2
Yuichiro Yada, Takeshi Mita, Akihiro Sanada, Ryuichi Yano, Ryohei Kanzaki, Douglas J Bakkum, Andreas Hierlemann, Hirokazu Takahashi
Self-organized criticality (SoC), a spontaneous dynamic state established and maintained in networks of moderate complexity, is a universal characteristic of neural systems. Such systems produce cascades of spontaneous activity that are typically characterized by power-law distributions and rich, stable spatiotemporal patterns (i.e., neuronal avalanches). Since the dynamics of the critical state confer advantages in information processing within neuronal networks, it is of great interest to determine how criticality emerges during development...
November 30, 2016: Neuroscience
https://www.readbyqxmd.com/read/27912162/serotonin-2a-receptor-5-ht2a-gene-promoter-variant-interacts-with-chronic-perceived-stress-to-modulate-resting-parasympathetic-activity-in-humans
#3
Chuan-Chia Chang, Wen-Hui Fang, Hsin-An Chang, Tieh-Ching Chang, Jia-Fwa Shyu, San-Yuan Huang
Decreased resting vagal (parasympathetic) tone is implicated in the development of stress-related disorders, including anxiety and depression. Chronic stress elevates the expression of serotonin 2A receptors (5-HT2A), while activation of 5-HT2A leads to inhibition of parasympathetic synaptic transmission. The T allele of the promoter variant, rs6311 (C>T), of the 5-HT2A gene has been shown to increase the 5-HT2A expression in vitro and to be associated with anxiety and depressive disorders. We thus hypothesized that the 5-HT2A functional polymorphism may influence resting vagal activity among persons with chronically high levels of perceived stress...
November 16, 2016: Psychoneuroendocrinology
https://www.readbyqxmd.com/read/27906389/emulation-of-synaptic-metaplasticity-in-memristors
#4
Xiaojian Zhu, Chao Du, YeonJoo Jeong, Wei D Lu
Recent studies have shown that nanoionic-based memristors can offer rich internal dynamics during ion movement that enables these solid-state devices to emulate various synaptic functions in biological systems naturally. The experimental observations can be explained within the 2nd-order memristor theoretical framework, which states that the device conductance (weight) can be determined by multiple internal state variables that can be modulated at different time scales and lead to different activity-dependent synaptic behaviors...
December 1, 2016: Nanoscale
https://www.readbyqxmd.com/read/27905555/the-complex-nature-of-calcium-cation-interactions-with-phospholipid-bilayers
#5
Adéla Melcrová, Sarka Pokorna, Saranya Pullanchery, Miriam Kohagen, Piotr Jurkiewicz, Martin Hof, Pavel Jungwirth, Paul S Cremer, Lukasz Cwiklik
Understanding interactions of calcium with lipid membranes at the molecular level is of great importance in light of their involvement in calcium signaling, association of proteins with cellular membranes, and membrane fusion. We quantify these interactions in detail by employing a combination of spectroscopic methods with atomistic molecular dynamics simulations. Namely, time-resolved fluorescent spectroscopy of lipid vesicles and vibrational sum frequency spectroscopy of lipid monolayers are used to characterize local binding sites of calcium in zwitterionic and anionic model lipid assemblies, while dynamic light scattering and zeta potential measurements are employed for macroscopic characterization of lipid vesicles in calcium-containing environments...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27896839/dopamine-elevates-and-lowers-astroglial-ca-2-through-distinct-pathways-depending-on-local-synaptic-circuitry
#6
Alistair Jennings, Olga Tyurikova, Lucie Bard, Kaiyu Zheng, Alexey Semyanov, Christian Henneberger, Dmitri A Rusakov
Whilst astrocytes in culture invariably respond to dopamine with cytosolic Ca(2+) rises, the dopamine sensitivity of astroglia in situ and its physiological roles remain unknown. To minimize effects of experimental manipulations on astroglial physiology, here we monitored Ca(2+) in cells connected via gap junctions to astrocytes loaded whole-cell with cytosolic indicators in area CA1 of acute hippocampal slices. Aiming at high sensitivity of [Ca(2+) ] measurements, we also employed life-time imaging of the Ca(2+) indicator Oregon Green BAPTA-1...
November 29, 2016: Glia
https://www.readbyqxmd.com/read/27895555/spike-timing-rigidity-is-maintained-in-bursting-neurons-under-pentobarbital-induced-anesthetic-conditions
#7
Risako Kato, Masanori Yamanaka, Eiko Yokota, Noriaki Koshikawa, Masayuki Kobayashi
Pentobarbital potentiates γ-aminobutyric acid (GABA)-mediated inhibitory synaptic transmission by prolonging the open time of GABAA receptors. However, it is unknown how pentobarbital regulates cortical neuronal activities via local circuits in vivo. To examine this question, we performed extracellular unit recording in rat insular cortex under awake and anesthetic conditions. Not a few studies apply time-rescaling theorem to detect the features of repetitive spike firing. Similar to these methods, we define an average spike interval locally in time using random matrix theory (RMT), which enables us to compare different activity states on a universal scale...
2016: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/27886522/increase-in-pas-induced-neuroplasticity-after-a-treatment-course-of-intranasal-ketamine-for-depression-report-of-three-cases-from-a-placebo-controlled-trial
#8
Verònica Gálvez, Stevan Nikolin, Kerrie-Anne Ho, Angelo Alonzo, Andrew A Somogyi, Colleen K Loo
BACKGROUND: Animal studies suggest that neural plasticity may play a role in the antidepressant effects of a single ketamine dose. However, the potential effects of repeated ketamine treatments on human neuroplasticity are unknown. METHODS: This pilot RCT study measured plasticity-induced changes before and after a ketamine course, in three treatment-resistant depressed subjects, who were randomized to receive 8 intranasal treatments of 100mg ketamine or 4.5mg midazolam...
November 4, 2016: Comprehensive Psychiatry
https://www.readbyqxmd.com/read/27881953/connectomic-analysis-of-brain-networks-novel-techniques-and-future-directions
#9
REVIEW
J Leonie Cazemier, Francisco Clascá, Paul H E Tiesinga
Brain networks, localized or brain-wide, exist only at the cellular level, i.e., between specific pre- and post-synaptic neurons, which are connected through functionally diverse synapses located at specific points of their cell membranes. "Connectomics" is the emerging subfield of neuroanatomy explicitly aimed at elucidating the wiring of brain networks with cellular resolution and a quantified accuracy. Such data are indispensable for realistic modeling of brain circuitry and function. A connectomic analysis, therefore, needs to identify and measure the soma, dendrites, axonal path, and branching patterns together with the synapses and gap junctions of the neurons involved in any given brain circuit or network...
2016: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/27874238/li-ion-synaptic-transistor-for-low-power-analog-computing
#10
Elliot J Fuller, Farid El Gabaly, François Léonard, Sapan Agarwal, Steven J Plimpton, Robin B Jacobs-Gedrim, Conrad D James, Matthew J Marinella, A Alec Talin
Nonvolatile redox transistors (NVRTs) based upon Li-ion battery materials are demonstrated as memory elements for neuromorphic computer architectures with multi-level analog states, "write" linearity, low-voltage switching and low power dissipation. Simulations of backpropagation using the device properties reaches ideal classification accuracy. Physics-based simulations predict energy costs per "write" operation of <10 aJ when scaled to 200 × 200 nm.
November 22, 2016: Advanced Materials
https://www.readbyqxmd.com/read/27872870/nanoscale-organization-of-synaptic-adhesion-proteins-revealed-by-single-molecule-localization-microscopy
#11
Ingrid Chamma, Florian Levet, Jean-Baptiste Sibarita, Matthieu Sainlos, Olivier Thoumine
The advent of superresolution imaging has created a strong need for both optimized labeling strategies and analysis methods to probe the nanoscale organization of complex biological structures. We present a thorough description of the distribution of synaptic adhesion proteins at the nanoscopic scale, namely presynaptic neurexin-[Formula: see text] ([Formula: see text]), and its two postsynaptic binding partners neuroligin-1 (Nlg1) and leucine-rich-repeat transmembrane protein 2 (LRRTM2). We monitored these proteins in the membrane of neurons by direct stochastic optical reconstruction microscopy, after live surface labeling with Alexa647-conjugated monomeric streptavidin...
October 2016: Neurophotonics
https://www.readbyqxmd.com/read/27870449/do-cortical-plasticity-mechanisms-differ-between-males-and-females
#12
James Dachtler, Kevin Fox
The difference between male and female behavior and male and female susceptibility to a number of neuropsychiatric conditions is not controversial. From a biological perspective, one might expect to see at least some of these differences underpinned by identifiable physical differences in the brain. This Mini-Review focuses on evidence that plasticity mechanisms differ between males and females and ask at what scale of organization the differences might exist, at the systems level, the circuits level, or the synaptic level...
January 2, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/27861918/maguk-dynamics-reveal-regional-and-developmental-specificity-of-synapse-stability
#13
Jonathan M Levy, Roger A Nicoll
Fast excitatory transmission in the brain requires localization of glutamate receptors to synapses. The MAGUK family of synaptic scaffolding proteins is critical for localization of glutamate receptors to synapses. Although the MAGUKs are well-studied in reduced preparations and young animals, little data exists on their role in adult animals. Here, we present a detailed developmental study of the role of the MAGUKs during rat development. We first confirm by knockdown experiments that MAGUKs are essential for glutamatergic transmission in young animals and cultured slices, and increases in PSD-95 by overexpression causes correlated increases in glutamatergic transmission...
November 8, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27859029/reactivation-of-seizure-related-changes-to-interictal-spike-shape-and-synchrony-during-postseizure-sleep-in-patients
#14
Mark R Bower, Michal T Kucewicz, Erik K St Louis, Fredric B Meyer, W Richard Marsh, Matt Stead, Gregory A Worrell
OBJECTIVE: Local field potentials (LFPs) arise from synchronous activation of millions of neurons, producing seemingly consistent waveform shapes and relative synchrony across electrodes. Interictal spikes (IISs) are LFPs associated with epilepsy that are commonly used to guide surgical resection. Recently, changes in neuronal firing patterns observed in the minutes preceding seizure onset were found to be reactivated during postseizure sleep, a process called seizure-related consolidation (SRC), due to similarities with learning-related consolidation...
November 18, 2016: Epilepsia
https://www.readbyqxmd.com/read/27855061/rotating-waves-during-human-sleep-spindles-organize-global-patterns-of-activity-that-repeat-precisely-through-the-night
#15
Lyle Muller, Giovanni Piantoni, Dominik Koller, Sydney S Cash, Eric Halgren, Terrence J Sejnowski
During sleep, the thalamus generates a characteristic pattern of transient, 11-15 Hz sleep spindle oscillations, which synchronize the cortex through large-scale thalamocortical loops. Spindles have been increasingly demonstrated to be critical for sleep-dependent consolidation of memory, but the specific neural mechanism for this process remains unclear. We show here that cortical spindles are spatiotemporally organized into circular wave-like patterns, organizing neuronal activity over tens of milliseconds, within the timescale for storing memories in large-scale networks across the cortex via spike-time dependent plasticity...
November 15, 2016: ELife
https://www.readbyqxmd.com/read/27853608/fossil-skulls-reveal-that-blood-flow-rate-to-the-brain-increased-faster-than-brain-volume-during-human-evolution
#16
Roger S Seymour, Vanya Bosiocic, Edward P Snelling
The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens, increases disproportionately when scaled against brain volume (the allometric exponent is 1...
August 2016: Royal Society Open Science
https://www.readbyqxmd.com/read/27852961/effect-of-antipsychotic-pharmacotherapy-on-clinical-outcomes-of-intermittent-theta-burst-stimulation-for-refractory-depression
#17
Laura Schulze, Gary Remington, Peter Giacobbe, Sidney H Kennedy, Daniel M Blumberger, Zafiris J Daskalakis, Jonathan Downar
Theta-burst stimulation is an emerging protocol for repetitive transcranial magnetic stimulation that takes 1-3 min to administer, yet offers equal/superior potency to conventional protocols lasting 30-60 min. However, preclinical evidence suggests that D2 receptor blockade may abolish the acute effects of theta-burst stimulation on synaptic facilitation or inhibition. As many patients presenting for repetitive transcranial magnetic stimulation are taking antipsychotic medications as augmentation for treatment-resistant depression, this finding is potentially concerning for the implementation of theta-burst stimulation in clinical settings...
November 9, 2016: Journal of Psychopharmacology
https://www.readbyqxmd.com/read/27812323/intrinsic-cellular-properties-and-connectivity-density-determine-variable-clustering-patterns-in-randomly-connected-inhibitory-neural-networks
#18
Scott Rich, Victoria Booth, Michal Zochowski
The plethora of inhibitory interneurons in the hippocampus and cortex play a pivotal role in generating rhythmic activity by clustering and synchronizing cell firing. Results of our simulations demonstrate that both the intrinsic cellular properties of neurons and the degree of network connectivity affect the characteristics of clustered dynamics exhibited in randomly connected, heterogeneous inhibitory networks. We quantify intrinsic cellular properties by the neuron's current-frequency relation (IF curve) and Phase Response Curve (PRC), a measure of how perturbations given at various phases of a neurons firing cycle affect subsequent spike timing...
2016: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/27797828/hybrid-scheme-for-modeling-local-field-potentials-from-point-neuron-networks
#19
Espen Hagen, David Dahmen, Maria L Stavrinou, Henrik Lindén, Tom Tetzlaff, Sacha J van Albada, Sonja Grün, Markus Diesmann, Gaute T Einevoll
With rapidly advancing multi-electrode recording technology, the local field potential (LFP) has again become a popular measure of neuronal activity in both research and clinical applications. Proper understanding of the LFP requires detailed mathematical modeling incorporating the anatomical and electrophysiological features of neurons near the recording electrode, as well as synaptic inputs from the entire network. Here we propose a hybrid modeling scheme combining efficient point-neuron network models with biophysical principles underlying LFP generation by real neurons...
October 20, 2016: Cerebral Cortex
https://www.readbyqxmd.com/read/27777283/parallel-evolution-of-cold-tolerance-within-drosophila-melanogaster
#20
John E Pool, Dylan T Braun, Justin B Lack
Drosophila melanogaster originated in tropical Africa before expanding into strikingly different temperate climates in Eurasia and beyond. Here, we find elevated cold tolerance in three distinct geographic regions: beyond the well-studied non-African case, we show that populations from the highlands of Ethiopia and South Africa have significantly increased cold tolerance as well. We observe greater cold tolerance in outbred versus inbred flies, but only in populations with higher inversion frequencies. Each cold-adapted population shows lower inversion frequencies than a closely-related warm-adapted population, suggesting that inversion frequencies may decrease with altitude in addition to latitude...
October 24, 2016: Molecular Biology and Evolution
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