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Synaptic scaling

Jean-Nicolas Audet, Lima Kayello, Simon Ducatez, Sara Perillo, Laure Cauchard, Jason T Howard, Lauren A O'Connell, Erich D Jarvis, Louis Lefebvre
Problem solving and innovation are key components of intelligence. We compare wild-caught individuals from two species that are close relatives of Darwin's finches, the innovative Loxigilla barbadensis , and its most closely related species in Barbados, the conservative Tiaris bicolor . We found an all-or-none difference in the problem-solving capacity of the two species. Brain RNA sequencing analyses revealed interspecific differences in genes related to neuronal and synaptic plasticity in the intrapallial neural populations (mesopallium and nidopallium), especially in the nidopallium caudolaterale, a structure functionally analogous to the mammalian prefrontal cortex...
March 2018: Science Advances
Matthew V Green, Jonathan D Raybuck, Xinwen Zhang, Mariah M Wu, Stanley A Thayer
A defining feature of HIV-associated neurocognitive disorder (HAND) is the loss of excitatory synaptic connections. Synaptic changes that occur during exposure to HIV appear to result, in part, from a homeostatic scaling response. Here we discuss the mechanisms of these changes from the perspective that they might be part of a coping mechanism that reduces synapses to prevent excitotoxicity. In transgenic animals expressing the HIV proteins Tat or gp120, the loss of synaptic markers precedes changes in neuronal number...
March 14, 2018: Neurochemical Research
Augusta Pisanu, Laura Boi, Giovanna Mulas, Saturnino Spiga, Sandro Fenu, Anna R Carta
Neuroinflammation is a main component of Parkinson's disease (PD) neuropathology, where unremitting reactive microglia and microglia-secreted soluble molecules such as cytokines, contribute to the neurodegenerative process as part of an aberrant immune reaction. Besides, pro-inflammatory cytokines, predominantly TNF-α, play an important neuromodulatory role in the healthy and diseased brain, being involved in neurotransmitter metabolism, synaptic scaling and brain plasticity. Recent preclinical studies have evidenced an exacerbated neuroinflammatory reaction in the striatum of parkinsonian rats that developed dyskinetic responses following L-DOPA administration...
March 14, 2018: Journal of Neural Transmission
Victor Matveev
Fundamental cell processes such as synaptic neurotransmitter release, endocrine hormone secretion, and myocyte contraction are controlled by highly localized calcium (Ca2+ ) signals resulting from brief openings of trans-membrane Ca2+ channels. On short temporal and spatial scales, the corresponding local Ca2+ nanodomains formed in the vicinity of a single or several open Ca2+ channels can be effectively approximated by quasi-stationary solutions. The rapid buffering approximation (RBA) is one of the most powerful of such approximations, and is based on the assumption of instantaneous equilibration of the bimolecular Ca2+ buffering reaction, combined with the conservation condition for the total Ca2+ and buffer molecule numbers...
March 13, 2018: Biophysical Journal
Mantas Mikaitis, Garibaldi Pineda García, James C Knight, Steve B Furber
SpiNNaker is a digital neuromorphic architecture, designed specifically for the low power simulation of large-scale spiking neural networks at speeds close to biological real-time. Unlike other neuromorphic systems, SpiNNaker allows users to develop their own neuron and synapse models as well as specify arbitrary connectivity. As a result SpiNNaker has proved to be a powerful tool for studying different neuron models as well as synaptic plasticity-believed to be one of the main mechanisms behind learning and memory in the brain...
2018: Frontiers in Neuroscience
Diego Z Carvalho, Erik K St Louis, David S Knopman, Bradley F Boeve, Val J Lowe, Rosebud O Roberts, Michelle M Mielke, Scott A Przybelski, Mary M Machulda, Ronald C Petersen, Clifford R Jack, Prashanthi Vemuri
Importance: Aging is associated with excessive daytime sleepiness (EDS), which has been linked to cognitive decline in the elderly. However, whether EDS is associated with the pathologic processes of Alzheimer disease remains unclear. Objective: To investigate whether EDS at baseline is associated with a longitudinal increase in regional β-amyloid (Aβ) accumulation in a cohort of elderly individuals without dementia. Design, Setting, and Participants: This prospective analysis included participants enrolled in the Mayo Clinic Study of Aging, a longitudinal population-based study in Olmsted County, Minnesota...
March 12, 2018: JAMA Neurology
D Calvetti, G Capo Rangel, L Gerardo Giorda, E Somersalo
The human brain is a small organ which uses a disproportional amount of the total metabolic energy production in the body. While it is well understood that the most significant energy sink is the maintenance of the neuronal membrane potential during the brain signaling activity, the role of astrocytes in the energy balance continues to be the topic of a lot of research. A key function of astrocytes, besides clearing glutamate from the synaptic clefts, is the potassium clearing after neuronal activation. Extracellular potassium plays a significant role in triggering neuronal firing, and elevated concentration of potassium may lead to abnormal firing pattern, e...
March 9, 2018: Journal of Theoretical Biology
Ivan Koychev, John Francis William Deakin, Wael El-Deredy, Corinna Haenschel
BACKGROUND: Working memory (WM) deficits are a core feature of schizophrenia. Electrophysiological studies suggest that impaired early visual processing may contribute to impaired WM in the visual domain. Abnormal N-methyl-D-aspartate (NMDA) receptor function has been implicated both in WM and in early visual processing deficits in schizophrenia. We investigated whether ketamine, a noncompetitive NMDA antagonist, would replicate in healthy volunteers the WM performance and early visual processing abnormalities we and others have reported in patients with schizophrenia...
April 2017: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
Leng-Duei Koh, Jingjie Yeo, Yeong Yuh Lee, Qunya Ong, Mingyong Han, Benjamin C-K Tee
The present review will introduce the basic concepts of silk-based electronics/optoelectronics including the latest technological advances on the use of silk fibroin in combination with other functional components, with an emphasis on improving the performance of next-generation silk-based materials. It also highlights the patterning of silk fibroin to produce micro/nano-scale features, as well as the functionalization of silk fibroin to impart antimicrobial (i.e. antibacterial) properties. Silk-based bioelectronics have great potential for advanced or futuristic bio-applications including e-skins, e-bandages, biosensors, wearable displays, implantable devices, artificial muscles, etc...
May 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Justyna O Ekert, Rebecca L Gould, Gemma Reynolds, Robert J Howard
OBJECTIVES: The objective of this study was to evaluate the effect of tumour necrosis factor-alpha inhibitors (TNF-αI) on Alzheimer's disease-associated pathology. DESIGN: A literature search of PubMed, Embase, PsychINFO, Web of Science, Scopus, and the Cochrane Library databases for human and animal studies that evaluated the use of TNF-αI was performed on 26 October 2016. RESULTS: The main outcomes assessed were cognition and behaviour, reduction in brain tissue mass, presence of plaques and tangles, and synaptic function...
March 7, 2018: International Journal of Geriatric Psychiatry
Premlal Balakrishna Pillai, Ashwani Kumar, Xiaoyao Song, Maria Merlyne De Souza
An electrochemical device capable of manifesting reversible charge storage at the interface of an active layer offers formidable advantages, such as low switching energy and long retention time, in realizing synaptic behavior for ultralow power neuromorphic systems. Contrary to a supercapacitor-based field-effect device that is prone to low memory retention due to fast discharge, a solid electrolyte-gated ZnO thin-film device exhibiting a battery-controlled charge storage mechanism via mobile charges at its interface with tantalum oxide is demonstrated...
March 7, 2018: ACS Applied Materials & Interfaces
Hui-Kai He, Rui Yang, Wen Zhou, He-Ming Huang, Jue Xiong, Lin Gan, Tian-You Zhai, Xin Guo
Monolayer of 2D transition metal dichalcogenides, with a thickness of less than 1 nm, paves a feasible path to the development of ultrathin memristive synapses, to fulfill the requirements for constructing large-scale high density 3D stacking neuromorphic chips. Herein, memristive devices based on monolayer n-MoS2 on p-Si substrate with a large self-rectification ratio, exhibiting photonic potentiation and electric habituation, are successfully fabricated. Versatile synaptic neuromorphic functions, such as potentiation/habituation, short-term/long-term plasticity, and paired-pulse facilitation, are successfully mimicked based on the inherent persistent photoconductivity performance and the volatile resistive switching behavior...
March 5, 2018: Small
Hao Yu, Hao Yan, Lifang Wang, Jun Li, Liwen Tan, Wei Deng, Qi Chen, Guigang Yang, Fuquan Zhang, Tianlan Lu, Jianli Yang, Keqing Li, Luxian Lv, Qingrong Tan, Hongyan Zhang, Xiao Xiao, Ming Li, Xin Ma, Fude Yang, Lingjiang Li, Chuanyue Wang, Tao Li, Dai Zhang, Weihua Yue
BACKGROUND: Antipsychotic drugs improve schizophrenia symptoms and reduce the frequency of relapse, but treatment response is highly variable. Little is known about the genetic factors associated with treatment response. We did a genome-wide association study of antipsychotic treatment response in patients with schizophrenia. METHODS: The discovery cohort comprised patients with schizophrenia from 32 psychiatric hospitals in China that are part of the Chinese Antipsychotics Pharmacogenomics Consortium...
March 1, 2018: Lancet Psychiatry
You Zhai, Jian Zhai
This paper uses a newly defined functional connectome and connectome values calculated in time domain of simulated neurotransmitter release (NTR) from an electrocorticogram (ECoG) to distinguish between conditioned and unconditioned stimuli. The NTR derived from multiple channels releasing one quantum at the same time suggests that one functional connectome occurs across those channels at that time. During the first 600 ms after conditional stimulation, the connectome indexes of the 64-channel NTR trains were sorted from the 8 to 20 Hz band obtained from filtered rabbit ECoGs recorded from the visual cortices...
2018: Frontiers in Behavioral Neuroscience
Kiryl D Piatkevich, Erica E Jung, Christoph Straub, Changyang Linghu, Demian Park, Ho-Jun Suk, Daniel R Hochbaum, Daniel Goodwin, Eftychios Pnevmatikakis, Nikita Pak, Takashi Kawashima, Chao-Tsung Yang, Jeffrey L Rhoades, Or Shemesh, Shoh Asano, Young-Gyu Yoon, Limor Freifeld, Jessica L Saulnier, Clemens Riegler, Florian Engert, Thom Hughes, Mikhail Drobizhev, Balint Szabo, Misha B Ahrens, Steven W Flavell, Bernardo L Sabatini, Edward S Boyden
We developed a new way to engineer complex proteins toward multidimensional specifications using a simple, yet scalable, directed evolution strategy. By robotically picking mammalian cells that were identified, under a microscope, as expressing proteins that simultaneously exhibit several specific properties, we can screen hundreds of thousands of proteins in a library in just a few hours, evaluating each along multiple performance axes. To demonstrate the power of this approach, we created a genetically encoded fluorescent voltage indicator, simultaneously optimizing its brightness and membrane localization using our microscopy-guided cell-picking strategy...
February 26, 2018: Nature Chemical Biology
Lijuan Man, Xiaoli Lv, Xiang-Dong Du, Guangzhong Yin, Xiaomin Zhu, Yingyang Zhang, Jair C Soares, Xu-Na Yang, Xingshi Chen, Xiang Yang Zhang
Evidence shows that BDNF may regulate activity-dependent forms of synaptic plasticity underlying learning and memory. Previous studies reported low BDNF levels and cognitive impairment in the early stage of schizophrenia. Our current study aimed to explore the association between serum BDNF and cognitive functions in first-episode drug-naïve (FEDN) patients with schizophrenia, which has been under-investigated. We recruited 80 FEDN patients and 80 healthy controls and examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and serum BDNF in both groups...
February 15, 2018: Psychiatry Research
Tim Benke, Stephen F Traynelis
Twenty years ago, we reported from the Collingridge Lab that a single-channel conductance increase through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type ionotropic glutamate receptors (AMPARs) could mediate one form of plasticity associated with long-term potentiation (LTP) in the hippocampus (Benke et al., Nature 395:793-797, 1998). Revealed through peak-scaled non-stationary fluctuation analysis (PS-NSFA, also known as noise analysis), this component of LTP could be exclusively mediated by direct increases in channel conductance or by increases in the number of high conductance synaptic AMPARs...
February 23, 2018: Neurochemical Research
Subhadip Basu, Punam Kumar Saha, Matylda Roszkowska, Marta Magnowska, Ewa Baczynska, Nirmal Das, Dariusz Plewczynski, Jakub Wlodarczyk
The observation and analysis of dendritic spines morphological changes poses a major challenge in neuroscience studies. The alterations of their density and/or morphology are indicators of the cellular processes involved in neural plasticity underlying learning and memory, and are symptomatic in neuropsychiatric disorders. Despite ongoing intense investigations in imaging approaches, the relationship between changes in spine morphology and synaptic function is still unknown. The existing quantitative analyses are difficult to perform and require extensive user intervention...
February 23, 2018: Scientific Reports
Romesh G Abeysuriya, Jonathan Hadida, Stamatios N Sotiropoulos, Saad Jbabdi, Robert Becker, Benjamin A E Hunt, Matthew J Brookes, Mark W Woolrich
Over long timescales, neuronal dynamics can be robust to quite large perturbations, such as changes in white matter connectivity and grey matter structure through processes including learning, aging, development and certain disease processes. One possible explanation is that robust dynamics are facilitated by homeostatic mechanisms that can dynamically rebalance brain networks. In this study, we simulate a cortical brain network using the Wilson-Cowan neural mass model with conduction delays and noise, and use inhibitory synaptic plasticity (ISP) to dynamically achieve a spatially local balance between excitation and inhibition...
February 23, 2018: PLoS Computational Biology
Robert Lindroos, Matthijs C Dorst, Kai Du, Marko Filipović, Daniel Keller, Maya Ketzef, Alexander K Kozlov, Arvind Kumar, Mikael Lindahl, Anu G Nair, Juan Pérez-Fernández, Sten Grillner, Gilad Silberberg, Jeanette Hellgren Kotaleski
The basal ganglia are involved in the motivational and habitual control of motor and cognitive behaviors. Striatum, the largest basal ganglia input stage, integrates cortical and thalamic inputs in functionally segregated cortico-basal ganglia-thalamic loops, and in addition the basal ganglia output nuclei control targets in the brainstem. Striatal function depends on the balance between the direct pathway medium spiny neurons (D1-MSNs) that express D1 dopamine receptors and the indirect pathway MSNs that express D2 dopamine receptors...
2018: Frontiers in Neural Circuits
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