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https://www.readbyqxmd.com/read/29675297/minimally-invasive-multimode-optical-fiber-microendoscope-for-deep-brain-fluorescence-imaging
#1
Shay Ohayon, Antonio Caravaca-Aguirre, Rafael Piestun, James J DiCarlo
A major open challenge in neuroscience is the ability to measure and perturb neural activity in vivo from well defined neural sub-populations at cellular resolution anywhere in the brain. However, limitations posed by scattering and absorption prohibit non-invasive multi-photon approaches for deep (>2mm) structures, while gradient refractive index (GRIN) endoscopes are relatively thick and can cause significant damage upon insertion. Here, we present a novel micro-endoscope design to image neural activity at arbitrary depths via an ultra-thin multi-mode optical fiber (MMF) probe that has 5-10X thinner diameter than commercially available micro-endoscopes...
April 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29666364/improved-calcium-sensor-gcamp-x-overcomes-the-calcium-channel-perturbations-induced-by-the-calmodulin-in-gcamp
#2
Yaxiong Yang, Nan Liu, Yuanyuan He, Yuxia Liu, Lin Ge, Linzhi Zou, Sen Song, Wei Xiong, Xiaodong Liu
GCaMP, one popular type of genetically-encoded Ca2+ indicator, has been associated with various side-effects. Here we unveil the intrinsic problem prevailing over different versions and applications, showing that GCaMP containing CaM (calmodulin) interferes with both gating and signaling of L-type calcium channels (CaV 1). GCaMP acts as an impaired apoCaM and Ca2+ /CaM, both critical to CaV 1, which disrupts Ca2+ dynamics and gene expression. We then design and implement GCaMP-X, by incorporating an extra apoCaM-binding motif, effectively protecting CaV 1-dependent excitation-transcription coupling from perturbations...
April 17, 2018: Nature Communications
https://www.readbyqxmd.com/read/29608857/stretchable-transparent-electrode-array-for-simultaneous-electrical-and-optical-interrogation-of-neural-circuits-in-vivo
#3
Jing Zhang, Xiaojun Liu, Wenjing Xu, Wenhan Luo, Ming Li, Fangbing Chu, Lu Xu, Anyuan Cao, Ji-Song Guan, Shiming Tang, Xiaojie Duan
Recent developments of transparent electrode arrays provide unique capability for simultaneous optical and electrical interrogation of neural circuits in brain. However, none of these electrode arrays possess the stretchability highly desired to interface with mechanically active neural systems, such as brain under injury, spinal cord and peripheral nervous system (PNS). Here we report a stretchable transparent electrode array from carbon nanotube (CNT) web-like thin films that retain excellent electrochemical performance and broad-band optical transparency under stretching, and are highly durable under cyclic stretching deformation...
April 2, 2018: Nano Letters
https://www.readbyqxmd.com/read/29464198/unraveling-synaptic-gcamp-signals-differential-excitability-and-clearance-mechanisms-underlying-distinct-ca-2-dynamics-in-tonic-and-phasic-excitatory-and-aminergic-modulatory-motor-terminals-in-drosophila
#4
Xiaomin Xing, Chun-Fang Wu
GCaMP is an optogenetic Ca2+ sensor widely used for monitoring neuronal activities but the precise physiological implications of GCaMP signals remain to be further delineated among functionally distinct synapses. The Drosophila neuromuscular junction (NMJ), a powerful genetic system for studying synaptic function and plasticity, consists of tonic and phasic glutamatergic and modulatory aminergic motor terminals of distinct properties. We report a first simultaneous imaging and electric recording study to directly contrast the frequency characteristics of GCaMP signals of the three synapses for physiological implications...
January 2018: ENeuro
https://www.readbyqxmd.com/read/29427611/imaging-pathological-activities-of-human-brain-tissue-in-organotypic-culture
#5
Caroline Le Duigou, Etienne Savary, Mélanie Morin-Brureau, Daniel Gomez-Dominguez, André Sobczyk, Farah Chali, Giampaolo Milior, Larissa Kraus, Jochen C Meier, Dimitri M Kullmann, Bertrand Mathon, Liset Menendez de la Prida, Georg Dorfmuller, Johan Pallud, Emmanuel Eugène, Stéphane Clemenceau, Richard Miles
BACKGROUND: Insights into human brain diseases may emerge from tissue obtained after operations on patients. However techniques requiring transduction of transgenes carried by viral vectors cannot be applied to acute human tissue. NEW METHOD: We show that organotypic culture techniques can be used to maintain tissue from patients with three different neurological syndromes for several weeks in vitro. Optimized viral vector techniques and promoters for transgene expression are described...
March 15, 2018: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/29382752/brain-state-dependent-astrocytic-ca-2-signals-are-coupled-to-both-positive-and-negative-bold-fmri-signals
#6
Maosen Wang, Yi He, Terrence J Sejnowski, Xin Yu
Astrocytic Ca2+ -mediated gliovascular interactions regulate the neurovascular network in situ and in vivo. However, it is difficult to measure directly both the astrocytic activity and fMRI to relate the various forms of blood-oxygen-level-dependent (BOLD) signaling to brain states under normal and pathological conditions. In this study, fMRI and GCaMP-mediated Ca2+ optical fiber recordings revealed distinct evoked astrocytic Ca2+ signals that were coupled with positive BOLD signals and intrinsic astrocytic Ca2+ signals that were coupled with negative BOLD signals...
February 13, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29357111/imaging-of-mitochondrial-and-cytosolic-ca-2-signals-in-cultured-astrocytes
#7
Nannan Zhang, Shinghua Ding
This unit provides a step-by-step protocol for constructing cell type- and mitochondria-targeted GCaMP genetically encoded Ca2+ indicators (GECIs) for mitochondrial Ca2+ imaging in astrocytes. Mitochondrial Ca2+ plays a critical role in controlling cytosolic Ca2+ buffering, energy metabolism, and cellular signal transduction. Mitochondrial Ca2+ overload contributes to various pathological conditions, including neurodegeneration and apoptotic cell death in neurological diseases. Live-cell mitochondrial Ca2+ imaging is an important approach to understand mitochondrial Ca2+ dynamics and thus cell physiology and pathology...
January 22, 2018: Current Protocols in Neuroscience
https://www.readbyqxmd.com/read/29122814/non-endoplasmic-reticulum-based-calr-calreticulin-can-coordinate-heterocellular-calcium-signaling-and-vascular-function
#8
Lauren A Biwer, Miranda E Good, Kwangseok Hong, Rahul K Patel, Neha Agrawal, Robin Looft-Wilson, Swapnil K Sonkusare, Brant E Isakson
OBJECTIVE: In resistance arteries, endothelial cell (EC) extensions can make contact with smooth muscle cells, forming myoendothelial junction at holes in the internal elastic lamina (HIEL). At these HIEL, calcium signaling is tightly regulated. Because Calr (calreticulin) can buffer ≈50% of endoplasmic reticulum calcium and is expressed throughout IEL holes in small arteries, the only place where myoendothelial junctions form, we investigated the effect of EC-specific Calr deletion on calcium signaling and vascular function...
January 2018: Arteriosclerosis, Thrombosis, and Vascular Biology
https://www.readbyqxmd.com/read/28930702/gcamp-expression-in-retinal-ganglion-cells-characterized-using-a-low-cost-fundus-imaging-system
#9
Yao-Chuan Chang, Steven T Walston, Robert H Chow, James D Weiland
OBJECTIVE: Virus-transduced, intracellular-calcium indicators are effective reporters of neural activity, offering the advantage of cell-specific labeling. Due to the existence of an optimal time window for the expression of calcium indicators, a suitable tool for tracking GECI expression in vivo following transduction is highly desirable. APPROACH: We developed a noninvasive imaging approach based on a custom-modified, low-cost fundus viewing system that allowed us to monitor and characterize in vivo bright-field and fluorescence images of the mouse retina...
October 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28921719/inflammation-alters-ampa-stimulated-calcium-responses-in-dorsal-striatal-d2-but-not-d1-spiny-projection-neurons
#10
Carissa D Winland, Nora Welsh, Alberto Sepulveda-Rodriguez, Stefano Vicini, Kathleen A Maguire-Zeiss
Neuroinflammation precedes neuronal loss in striatal neurodegenerative diseases and can be exacerbated by the release of proinflammatory molecules by microglia. These molecules can affect trafficking of AMPARs. The preferential trafficking of calcium-permeable versus impermeable AMPARs can result in disruptions of [Ca(2+) ]i and alter cellular functions. In striatal neurodegenerative diseases, changes in [Ca(2+) ]i and L-type voltage-gated calcium channels (VGCCs) have been reported. Therefore, this study sought to determine whether a proinflammatory environment alters AMPA-stimulated [Ca(2+) ]i through calcium-permeable AMPARs and/or L-type VGCCs in dopamine-2- and dopamine-1-expressing striatal spiny projection neurons (D2 and D1 SPNs) in the dorsal striatum...
November 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28917183/visualisation-of-an-nspef-induced-calcium-wave-using-the-genetically-encoded-calcium-indicator-gcamp-in-u87-human-glioblastoma-cells
#11
Lynn Carr, Sylvia M Bardet, Delia Arnaud-Cormos, Philippe Leveque, Rodney P O'Connor
Cytosolic, synthetic chemical calcium indicators are typically used to visualise the rapid increase in intracellular calcium ion concentration that follows nanosecond pulsed electric field (nsPEF) application. This study looks at the application of genetically encoded calcium indicators (GECIs) to investigate the spatiotemporal nature of nsPEF-induced calcium signals using fluorescent live cell imaging. Calcium responses to 44kV/cm, 10ns pulses were observed in U87-MG cells expressing either a plasma membrane targeted GECI (GCaMP5-G), or one cytosolically expressed (GCaMP6-S), and compared to the response of cells loaded with cytosolic or plasma membrane targeted chemical calcium indicators...
February 2018: Bioelectrochemistry
https://www.readbyqxmd.com/read/28874729/ratiometric-matryoshka-biosensors-from-a-nested-cassette-of-green-and-orange-emitting-fluorescent-proteins
#12
Cindy Ast, Jessica Foret, Luke M Oltrogge, Roberto De Michele, Thomas J Kleist, Cheng-Hsun Ho, Wolf B Frommer
Sensitivity, dynamic and detection range as well as exclusion of expression and instrumental artifacts are critical for the quantitation of data obtained with fluorescent protein (FP)-based biosensors in vivo. Current biosensors designs are, in general, unable to simultaneously meet all these criteria. Here, we describe a generalizable platform to create dual-FP biosensors with large dynamic ranges by employing a single FP-cassette, named GO-(Green-Orange) Matryoshka. The cassette nests a stable reference FP (large Stokes shift LSSmOrange) within a reporter FP (circularly permuted green FP)...
September 5, 2017: Nature Communications
https://www.readbyqxmd.com/read/28742117/comparison-of-gcamp3-and-gcamp6f-for-studying-astrocyte-ca2-dynamics-in-the-awake-mouse-brain
#13
COMPARATIVE STUDY
Liang Ye, Mateen A Haroon, Angelica Salinas, Martin Paukert
In recent years it has become increasingly clear that astrocytes play a much more active role in neural processes than the traditional view of them as supporting cells suggests. Although not electrically excitable, astrocytes exhibit diverse Ca2+ dynamics across spatial and temporal scales, more or less dependent on the animal's behavioral state. Ca2+ dynamics range from global elevations lasting multiple seconds encompassing the soma up to the finest processes, to short elevations restricted to so-called microdomains within fine processes...
2017: PloS One
https://www.readbyqxmd.com/read/28599354/a-profile-of-auditory-responsive-neurons-in-the-larval-zebrafish-brain
#14
Gilles Vanwalleghem, Lucy A Heap, Ethan K Scott
Many features of auditory processing are conserved among vertebrates, but the degree to which these pathways are established at early stages is not well explored. In this study, we have observed single cell activity throughout the brains of larval zebrafish with the goal of identifying the cellular responses, brain regions, and brain-wide pathways through which these larvae perceive and process auditory stimuli. Using GCaMP and selective plane illumination microscopy, we find strong responses to auditory tones ranging from 100 Hz to 400 Hz...
June 9, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28596596/optical-mapping-of-neuronal-activity-during-seizures-in-zebrafish
#15
L Turrini, C Fornetto, G Marchetto, M C Müllenbroich, N Tiso, A Vettori, F Resta, A Masi, G Mannaioni, F S Pavone, F Vanzi
Mapping neuronal activity during the onset and propagation of epileptic seizures can provide a better understanding of the mechanisms underlying this pathology and improve our approaches to the development of new drugs. Recently, zebrafish has become an important model for studying epilepsy both in basic research and in drug discovery. Here, we employed a transgenic line with pan-neuronal expression of the genetically-encoded calcium indicator GCaMP6s to measure neuronal activity in zebrafish larvae during seizures induced by pentylenetretrazole (PTZ)...
June 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28501905/investigation-of-pain-mechanisms-by-calcium-imaging-approaches
#16
REVIEW
Michael Anderson, Qin Zheng, Xinzhong Dong
Due to the complex circuitry and plethora of cell types involved in somatosensation, it is becoming increasingly important to be able to observe cellular activity at the population level. In addition, since cells rely on an intricate variety of extracellular factors, it is important to strive to maintain the physiological environment. Many electrophysiological techniques require the implementation of artificially-produced physiological environments and it can be difficult to assess the activity of many cells simultaneously...
February 2018: Neuroscience Bulletin
https://www.readbyqxmd.com/read/28248351/extended-depth-of-field-microscopy-with-a-high-speed-deformable-mirror
#17
William J Shain, Nicholas A Vickers, Bennett B Goldberg, Thomas Bifano, Jerome Mertz
We present a wide-field fluorescence microscopy add-on that provides a fast, light-efficient extended depth-of-field (EDOF) using a deformable mirror with an update rate of 20 kHz. Out-of-focus contributions in the raw EDOF images are suppressed with a deconvolution algorithm derived directly from the microscope 3D optical transfer function. Demonstrations of the benefits of EDOF microscopy are shown with GCaMP-labeled mouse brain tissue.
March 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28235895/spike-and-neuropeptide-dependent-mechanisms-control-gnrh-neuron-nerve-terminal-ca-2-over-diverse-time-scales
#18
Karl J Iremonger, Robert Porteous, Allan E Herbison
Fast cell-to-cell communication in the brain is achieved by action potential-dependent synaptic release of neurotransmitters. The fast kinetics of transmitter release are determined by transient Ca(2+) elevations in presynaptic nerve terminals. Neuromodulators have previously been shown to regulate transmitter release by inhibiting presynaptic Ca(2+) influx. Few studies to date have demonstrated the opposite, that is, neuromodulators directly driving presynaptic Ca(2+) rises and increases in nerve terminal excitability...
March 22, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28195691/the-gcamp-r-family-of-genetically-encoded-ratiometric-calcium-indicators
#19
Jung-Hwa Cho, Carter J Swanson, Jeannie Chen, Ang Li, Lisa G Lippert, Shannon E Boye, Kasey Rose, Sivaraj Sivaramakrishnan, Cheng-Ming Chuong, Robert H Chow
We report on GCaMP-Rs, a new family of genetically encoded ratiometric calcium indicators that extend the virtues of the GCaMP proteins to ratiometric measurements. We have engineered a tandem construct of calcium-dependent GCaMP and calcium-independent mCherry fluorescent proteins. The tandem design assures that the two proteins localize in the same cellular compartment(s) and facilitates pixelwise ratiometric measurements; however, Förster resonance energy transfer (FRET) between the fluorophores reduces brightness of the sensor by up to half (depending on the GCaMP variant)...
April 21, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28160463/mapping-cortical-mesoscopic-networks-of-single-spiking-cortical-or-sub-cortical-neurons
#20
Dongsheng Xiao, Matthieu P Vanni, Catalin C Mitelut, Allen W Chan, Jeffrey M LeDue, Yicheng Xie, Andrew Cn Chen, Nicholas V Swindale, Timothy H Murphy
Understanding the basis of brain function requires knowledge of cortical operations over wide-spatial scales, but also within the context of single neurons. In vivo, wide-field GCaMP imaging and sub-cortical/cortical cellular electrophysiology were used in mice to investigate relationships between spontaneous single neuron spiking and mesoscopic cortical activity. We make use of a rich set of cortical activity motifs that are present in spontaneous activity in anesthetized and awake animals. A mesoscale spike-triggered averaging procedure allowed the identification of motifs that are preferentially linked to individual spiking neurons by employing genetically targeted indicators of neuronal activity...
February 4, 2017: ELife
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