Готові списки джерел за темами / Optical voltage imaging

Добірка наукової літератури з теми "Optical voltage imaging"

Автор: Grafiati
Опубліковано: 10 грудня 2022
Оновлено: 28 січня 2023

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Статті в журналах з теми "Optical voltage imaging"

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Meng, Xin, Lex Huismans, Teun Huijben, Greta Szabo, Ruud van Tol, Izak de Heer, Srividya Ganapathy, and Daan Brinks. "A compact microscope for voltage imaging." Journal of Optics 24, no. 5 (April 1, 2022): 054004. http://dx.doi.org/10.1088/2040-8986/ac5dd5.

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Abstract Voltage imaging and optogenetics offer new routes to optically detect and influence neural dynamics. Optimized hardware is necessary to make the most of these new techniques. Here we present the Octoscope, a versatile, multimodal device for all-optical electrophysiology. We illustrate its concept and design and demonstrate its capability to perform both 1-photon and 2-photon voltage imaging with spatial and temporal light patterning, in both inverted and upright configurations, in vitro and in vivo.
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Chien, Miao-Ping, Daan Brinks, Guilherme Testa-Silva, He Tian, F. Phil Brooks, Yoav Adam, William Bloxham, Benjamin Gmeiner, Simon Kheifets, and Adam E. Cohen. "Photoactivated voltage imaging in tissue with an archaerhodopsin-derived reporter." Science Advances 7, no. 19 (May 2021): eabe3216. http://dx.doi.org/10.1126/sciadv.abe3216.

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Анотація:
Photoactivated genetically encoded voltage indicators (GEVIs) have the potential to enable optically sectioned voltage imaging at the intersection of a photoactivation beam and an imaging beam. We developed a pooled high-throughput screen to identify archaerhodopsin mutants with enhanced photoactivation. After screening ~105 cells, we identified a novel GEVI, NovArch, whose one-photon near-infrared fluorescence is reversibly enhanced by weak one-photon blue or two-photon near-infrared excitation. Because the photoactivation leads to fluorescent signals catalytically rather than stoichiometrically, high fluorescence signals, optical sectioning, and high time resolution are achieved simultaneously at modest blue or two-photon laser power. We demonstrate applications of the combined molecular and optical tools to optical mapping of membrane voltage in distal dendrites in acute mouse brain slices and in spontaneously active neurons in vivo.
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3

Steigerwald, Michael D. G. "Ultra Low Voltage BSE Imaging." Microscopy Today 11, no. 6 (December 2003): 26–29. http://dx.doi.org/10.1017/s1551929500053414.

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Анотація:
LEO's field emission scanning electron microscopes are all based an the “GEMINI” principle as shown in figure 1. In order to reduce aberrations and sensitivity to interfering stray-fields the electron optical column possesses a positively biased booster that shifts the energy of the primary electrons. The incident beam is focussed by a combination of a magnetic lens with an axial gap that avoids field leakage to the specimen and an electrostatic retarding lens formed by the beam booster together with the grounded pole piece cap. Shortly before the electrons hit the specimen they are decelerated down to the desired primary energy.
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Nelson, D. A., and L. C. Katz. "Optical imaging of brain slice preparations using voltage sensitive dyes." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 810–11. http://dx.doi.org/10.1017/s0424820100140427.

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Анотація:
Fast responding, biological membrane-soluble voltage sensitive dyes are probes which make it possible to directly monitor the electrical activity of neuronal tissues with both high temporal and high spatial resolution. High temporal resolution is desirable because of the millisecond time scale on which neuronal events occur. High spatial resolution is desirable to better reveal the complex interactions between different regions of neural circuits.Taking full advantage of the promise of voltage sensitive dyes can be both difficult and expensive. Tissues stained with these dyes undergo very small (often less than one part in a thousand) relative changes in fluorescence in response to changes in transmembrane potential. The signal-to-noise ratio is similarly small for these responses. Finally, the responses are very fast. Most major components of the signal rise to their maximum and then disappear within 15 milliseconds of stimulation (figure 1).Because standard video cameras are inadequate for recording the very small and very fast optical signals transduced by voltage sensitive dyes, specialized detection equipment is required. This entails a high cost per pixel, often limiting the practial number of detector elements to a few hundred or even less.
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5

Zhou, Yuecheng, Erica Liu, Holger Müller, and Bianxiao Cui. "Optical Electrophysiology: Toward the Goal of Label-Free Voltage Imaging." Journal of the American Chemical Society 143, no. 28 (June 30, 2021): 10482–99. http://dx.doi.org/10.1021/jacs.1c02960.

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6

Zhang, Yingqiu, Xing Liu, Qiaohua Wu, Wenfeng Li, and Chunlei Li. "Slow Light Effect and Tunable Channel in Graphene Grating Plasmonic Waveguide." Photonics 9, no. 2 (January 20, 2022): 54. http://dx.doi.org/10.3390/photonics9020054.

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Анотація:
A graphene plasmon waveguide composed of silicon grating substrate and a silica separator is proposed to generate the slow-light effect. A bias voltage is applied to tune the optical conductivity of graphene. The tunability of the slow-light working channel can be achieved due to the adjustable bias voltage. With an increase in the bias voltage, the working channel exhibited obvious linear blue-shift. The linear correlation coefficient between the working channel and the bias voltage was up to 0.9974. The average value of the normalized delay bandwidth product (NDBP) with different bias voltages was 3.61. In addition, we also studied the tunable group velocity at a specific working channel. Due to the tunability of this miniaturized waveguide structure, it can be used in a variety of applications including optical storage devices, optical buffers and optical switches.
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7

Herron, Todd J., Peter Lee, and José Jalife. "Optical Imaging of Voltage and Calcium in Cardiac Cells & Tissues." Circulation Research 110, no. 4 (February 17, 2012): 609–23. http://dx.doi.org/10.1161/circresaha.111.247494.

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8

Martin, Douglas, Samuel Beilin, Brett Hamilton, Darin York, Philip Baker, and Wai-Yat Leung. "Application of Advanced Back-Side Optical Techniques in ASICs." Microscopy Today 21, no. 3 (May 2013): 30–35. http://dx.doi.org/10.1017/s1551929513000540.

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Анотація:
Failure analysis is important in determining root cause for appropriate corrective action. In order to perform failure analysis of microelectronic application-specific integrated circuits (ASICs) delidding the device is often required. However, determining root cause from the front side is not always possible due to shadowing effects caused by the ASIC metal interconnects. Therefore, back-side polishing is used to reveal an unobstructed view of the ASIC silicon transistors. This paper details how back-side polishing in conjunction with laser-scanned imaging (LSI), laser voltage imaging (LVI), laser voltage probing (LVP), photon emission microscopy (PEM), and laser-assisted device alterations (LADA) were used to uncover the root cause of failure of two ASICs.
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Kunori, Nobuo, and Ichiro Takashima. "An Implantable Cranial Window Using a Collagen Membrane for Chronic Voltage-Sensitive Dye Imaging." Micromachines 10, no. 11 (November 18, 2019): 789. http://dx.doi.org/10.3390/mi10110789.

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Анотація:
Incorporating optical methods into implantable neural sensing devices is a challenging approach for brain–machine interfacing. Specifically, voltage-sensitive dye (VSD) imaging is a powerful tool enabling visualization of the network activity of thousands of neurons at high spatiotemporal resolution. However, VSD imaging usually requires removal of the dura mater for dye staining, and thereafter the exposed cortex needs to be protected using an optically transparent artificial dura. This is a major disadvantage that limits repeated VSD imaging over the long term. To address this issue, we propose to use an atelocollagen membrane as the dura substitute. We fabricated a small cranial chamber device, which is a tubular structure equipped with a collagen membrane at one end of the tube. We implanted the device into rats and monitored neural activity in the frontal cortex 1 week following surgery. The results indicate that the collagen membrane was chemically transparent, allowing VSD staining across the membrane material. The membrane was also optically transparent enough to pass light; forelimb-evoked neural activity was successfully visualized through the artificial dura. Because of its ideal chemical and optical manipulation capability, this collagen membrane may be widely applicable in various implantable neural sensors.
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10

Wang, Dongsheng, Shane McMahon, Zhen Zhang, and Meyer B. Jackson. "Hybrid voltage sensor imaging of electrical activity from neurons in hippocampal slices from transgenic mice." Journal of Neurophysiology 108, no. 11 (December 1, 2012): 3147–60. http://dx.doi.org/10.1152/jn.00722.2012.

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Анотація:
Gene targeting with genetically encoded optical voltage sensors brings the methods of voltage imaging to genetically defined neurons and offers a method of studying circuit activity in these selected populations. The present study reports the targeting of genetically encoded hybrid voltage sensors (hVOS) to neurons in transgenic mice. The hVOS family of probes employs a membrane-targeted fluorescent protein, which generates voltage-dependent fluorescence changes in the presence of dipicrylamine (DPA) as the result of a voltage-dependent optical interaction between the two molecules. We generated transgenic mice with two different high-performance hVOS probes under control of a neuron-specific thy-1 promoter. Hippocampal slices from these animals present distinct spatial patterns of expression, and electrical stimulation evoked fluorescence changes as high as 3%. Glutamate receptor and Na+ channel antagonists blocked these responses. One hVOS probe tested here harbors an axonal targeting motif (from GAP-43) and shows preferential expression in axons; this probe can thus report axonal voltage changes. Voltage imaging in transgenic mice expressing hVOS probes opens the door to the study of functional activity in genetically defined populations of neurons in intact neural circuits.
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Більше джерел

Дисертації з теми "Optical voltage imaging"

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Raguet, Hugo. "A Signal Processing Approach to Voltage-Sensitive Dye Optical Imaging." Thesis, Paris 9, 2014. http://www.theses.fr/2014PA090031/document.

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Анотація:
L’imagerie optique par colorant potentiométrique est une méthode d’enregistrement de l’activité corticale prometteuse, mais dont le potentiel réel est limité par la présence d’artefacts et d’interférences dans les acquisitions. À partir de modèles existant dans la littérature, nous proposons un modèle génératif du signal basé sur un mélange additif de composantes, chacune contrainte dans une union d’espaces linéaires déterminés par son origine biophysique. Motivés par le problème de séparation de composantes qui en découle, qui est un problème inverse linéaire sous-déterminé, nous développons : (1) des régularisations convexes structurées spatialement, favorisant en particulier des solutions parcimonieuses ; (2) un nouvel algorithme proximal de premier ordre pour minimiser efficacement la fonctionnelle qui en résulte ; (3) des méthodes statistiques de sélection de paramètre basées sur l’estimateur non biaisé du risque de Stein. Nous étudions ces outils dans un cadre général, et discutons leur utilité pour de nombreux domaines des mathématiques appliqués, en particulier pour les problèmes inverses ou de régression en grande dimension. Nous développons par la suite un logiciel de séparation de composantes en présence de bruit, dans un environnement intégré adapté à l’imagerie optique par colorant potentiométrique. Finalement, nous évaluons ce logiciel sur différentes données, synthétiques et réelles, montrant des résultats encourageants quant à la possibilité d’observer des dynamiques corticales complexes
Voltage-sensitive dye optical imaging is a promising recording modality for the cortical activity, but its practical potential is limited by many artefacts and interferences in the acquisitions. Inspired by existing models in the literature, we propose a generative model of the signal, based on an additive mixtures of components, each one being constrained within an union of linear spaces, determined by its biophysical origin. Motivated by the resulting component separation problem, which is an underdetermined linear inverse problem, we develop: (1) convex, spatially structured regularizations, enforcing in particular sparsity on the solutions; (2) a new rst-order proximal algorithm for minimizing e›ciently the resulting functional; (3) statistical methods for automatic parameters selection, based on Stein’s unbiased risk estimate.We study thosemethods in a general framework, and discuss their potential applications in variouselds of applied mathematics, in particular for large scale inverse problems or regressions. We develop subsequently a soŸware for noisy component separation, in an integrated environment adapted to voltage-sensitive dye optical imaging. Finally, we evaluate this soŸware on dišerent data set, including synthetic and real data, showing encouraging perspectives for the observation of complex cortical dynamics
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2

Xu, Chen. "Low voltage CMOS digital imaging architecture with device scaling considerations /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20XU.

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Анотація:
Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 131-136). Also available in electronic version. Access restricted to campus users.
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3

Ma, Pei. "OPTICAL IMAGING OF EMBRYONIC CARDIAC CONDUCTION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1464714110.

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4

Jain, Ankur. "Low voltage, MEMS-based reflective and refractive optical scanners for endoscopic biomedical imaging." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015728.

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5

Qureshi, Muhammad Shakeel. "Integrated front-end analog circuits for mems sensors in ultrasound imaging and optical grating based microphone." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29613.

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Анотація:
Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Hasler, Paul; Committee Co-Chair: Degertekin, Levent; Committee Member: Anderson, David; Committee Member: Ayazi, Farrokh; Committee Member: Brand, Oliver; Committee Member: Hesketh, Peter. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Montardy, Quentin. "Lier l'activité de population de neurones du cortex visuel primaire avec le comportement oculomoteur : des saccades de fixation à V1, et de V1 à la réponse de suivi oculaire." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM5069.

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Анотація:
Nous avons analysé l'activité de population au sein du cortex visuel primaire en vue de comprendre (i) les mécanismes mis en jeu lors de l'intégration de l'information visuelle suite à un mouvement oculaire, et inversement (ii) de l'influence du traitement effectué au niveau de V1 sur la génération d'un mouvement oculaire.1. Nous avons enregistré des saccades de fixation, et mis en relation, essai par essai, ces mouvements avec la représentation de la position d'un stimulus local dans V1. Après une saccade de fixation, l'activité se déplace de façon cohérente dans V1. Le décours temporel des réponses au niveau des foyers pre- et post-saccadiques montre une dynamique biphasique. La taille du foyer d'activité augmente. Nous proposons que le comportement des populations de neurones s'explique par deux phénomènes principaux : (i) La réponse suppressive précoce attribuable à la décharge corollaire (ii) de connections latérales qui réactiveraient le foyer pre-saccadique.2. Nous avons enregistré l'OFR, et cherché à savoir si la réponse de V1 l'influençait. Les latences VSD précèdent les latences OFR. Il n'existe pas de corrélation à l'essai unique. Nous avons montré que la force et la dynamique des réponses de V1 n'étaient pas prédictives de l'OFR. La distance de la périphérie à un effet sur la réponse VSD, mais pas sur l'OFR. La dynamique de propagation de cette suppression, nous avons montré deux phases : une précoce sur l'ensemble de la carte, et une plus périphérique tardive. Nous proposons que la suppression précoce soit originaire de projections en retour de structures comme MT et MST, alors que la suppression plus lente s'explique par les connections horizontales
We analyzed population activity in V1 to understand (i) the consequence of eye movements on integration of visual information, and (ii) the influence of the processing performed at the level of V1 on the generation of eye movements.1. We recorded fixational saccades, relating, trial-by-trial, these eye movements with the representation of the position of a local stimulus in V1. After a fixational saccade, activity moves consistently in V1. However, the time-course of responses display a biphasic dynamic. This results in a global increase of the extent of cortical activity representing the local stimulus. We propose that the behavior of populations of neurons studied is explained by the contribution of two main phenomena: (i) an early suppressive response that could be attributed to the corollary discharge and (ii) the lateral connections generating lateral interactions between pre and post-saccadic lci of activity.2. We recorded the ocular following response, determining whether the response of V1 influences the oculomotor response. We studied the contrast response function of the population V1 activity and the OFR. The dynamics of CRF for a local stimulus are similar and shifted in time. We found no correlations between the single trial latencies between V1 and the OFR. At the chosen scale, surround suppression was found to be distance-dependent only in V1. The dynamics of the surround suppression shows two phases: an early suppression present over a wide cortical area, and a later peripheral spread. We propose that the early surround suppression originates from feedback from MT and MST, while the later is explained by the horizontal connections
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Vacher, Jonathan. "Synthèse de textures dynamiques pour l'étude de la vision en psychophysique et électrophysiologie." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLED005/document.

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Анотація:
Le but de cette thèse est de proposer une modélisation mathématique des stimulations visuelles afin d'analyser finement des données expérimentales en psychophysique et en électrophysiologie. Plus précis\'ement, afin de pouvoir exploiter des techniques d'analyse de données issues des statistiques Bayésiennes et de l'apprentissage automatique, il est nécessaire de développer un ensemble de stimulations qui doivent être dynamiques, stochastiques et d'une complexité paramétrée. Il s'agit d'un problème important afin de comprendre la capacité du système visuel à intégrer et discriminer différents stimuli. En particulier, les mesures effectuées à de multiples échelles (neurone, population de neurones, cognition) nous permette d'étudier les sensibilités particulières des neurones, leur organisation fonctionnelle et leur impact sur la prise de décision. Dans ce but, nous proposons un ensemble de contributions théoriques, numériques et expérimentales, organisées autour de trois axes principaux : (1) un modèle de synthèse de textures dynamiques Gaussiennes spécialement paramétrée pour l'étude de la vision; (2) un modèle d'observateur Bayésien rendant compte du biais positif induit par fréquence spatiale sur la perception de la vitesse; (3) l'utilisation de méthodes d'apprentissage automatique pour l'analyse de données obtenues en imagerie optique par colorant potentiométrique et au cours d'enregistrements extra-cellulaires. Ce travail, au carrefour des neurosciences, de la psychophysique et des mathématiques, est le fruit de plusieurs collaborations interdisciplinaires
The goal of this thesis is to propose a mathematical model of visual stimulations in order to finely analyze experimental data in psychophysics and electrophysiology. More precisely, it is necessary to develop a set of dynamic, stochastic and parametric stimulations in order to exploit data analysis techniques from Bayesian statistics and machine learning. This problem is important to understand the visual system capacity to integrate and discriminate between stimuli. In particular, the measures performed at different scales (neurons, neural population, cognition) allow to study the particular sensitivities of neurons, their functional organization and their impact on decision making. To this purpose, we propose a set of theoretical, numerical and experimental contributions organized around three principal axes: (1) a Gaussian dynamic texture synthesis model specially crafted to probe vision; (2) a Bayesian observer model that accounts for the positive effect of spatial frequency over speed perception; (3) the use of machine learning techniques to analyze voltage sensitive dye optical imaging and extracellular data. This work, at the crossroads of neurosciences, psychophysics and mathematics is the fruit of several interdisciplinary collaborations
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Han, Mengke. "Intracellular delivery and voltage sensitivity of nanomaterials for the optical imaging of neuronal activity." Thesis, 2022. https://hdl.handle.net/2440/136060.

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Анотація:
Monitoring the electrical signals generated by neurons to transmit information, is central to understanding how the brain and nervous systems work. The photoluminescence (PL) of some nanomaterials, such as semiconductor quantum dots (QDs) and fluorescent nanodiamonds (NDs), has shown higher sensitivity to electrical fields than that of any previously reported probes, which may address the persistent challenge of robust optical voltage imaging. The fundamental issue for implementing voltage-sensitive nanomaterials (VSM) in live neurons is their delivery into the plasma membrane bilayer. Currently, the delivery has been demonstrated on QDs via their spontaneous insertion directly into the plasma membrane bilayer, or indirectly into the bilayer of liposomes that later fuse with the plasma membrane. In both methods, QDs are introduced from the extracellular space and implemented to image the activity of neuronal assemblies. The first part of this thesis explores the implementation of VSM in another scenario, i.e., the voltage imaging from multiple sites on single neurons. After direct intracellular delivery, amphiphilic nanomaterials are expected to spread into distal processes and insert into the plasma membrane bilayer, being able to monitor the electrical activity in the smallest neuronal structures, such as dendritic spines. Here, the intracellular delivery of nontargeted QDs as an example, has been demonstrated by microelectrophoresis technique, where electrical currents were applied to eject charged QDs through fine-tipped glass micropipettes into living cells. The amount of delivered QDs was finely controlled by tuning the ejection duration, which had a substantial impact on preserving short-term and long-term cell health. Delivered QDs were homogeneously distributed throughout the cytoplasm and presented pure Brownian diffusion without endosomal entrapment. These original and promising results lay the foundation to apply the microelectrophoresis technique to other VSM, including the protocol for preparing nanomaterials suspension and the required tip sizes of micropipettes, which are key to their successful intracellular loading. Another fundamental issue is ascertaining the PL responses of these nanomaterials to applied voltage modulations. The second part of this thesis describes the fabrication of a multilayer device that can apply a homogeneous electric field to the embedded nanomaterials (NDs as an example). By using ultrasonication, NDs were well dispersed as single particles within the device, where the PL responses of individual NDs can be examined. Other fabrication details, such as film thickness and electrode deposition, were also described. These results provide a high-throughput screening platform to characterize the voltage sensitivities of different nanomaterials, which helps to iteratively improve their design and synthesis, including composition, size, shape, and band alignment. Collectively, the findings in this thesis provide a significant contribution to the unique interface of neuroscience and nanomaterials regarding the optical visualization of neuronal activity. The pioneering work here facilitates the future use of microelectrophoresis technique to deliver various VSM for multisite voltage imaging of single neurons. The deployment of the multilayer device promotes the development and optimization of new nanomaterials with enhanced voltage sensitivity. With these fundamental challenges to be addressed in the near future, real-time in vivo voltage imaging may be attainable in relevant animal models to elucidate the complex function of brain and nervous systems.
Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2022
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9

Onat, Selim. "Sensory Integration under Natural Conditions: a Theoretical, Physiological and Behavioral Approach." Doctoral thesis, 2011. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-201109028314.

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Анотація:
We can affirm to apprehend a system in its totality only when we know how it behaves under its natural operating conditions. However, in the face of the complexity of the world, science can only evolve by simplifications, which paradoxically hide a good deal of the very mechanisms we are interested in. On the other hand, scientific enterprise is very tightly related to the advances in technology and the latter inevitably influences the manner in which the scientific experiments are conducted. Due to this factor, experimental conditions which would have been impossible to bring into laboratory not more than 20 years ago, are today within our reach. This thesis investigates neuronal integrative processes by using a variety of theoretical and experimental techniques wherein the approximation of ecologically relevant conditions within the laboratory is the common denominator. The working hypothesis of this thesis is that neurons and neuronal systems, in the sensory and higher cortices, are specifically adapted, as a result of evolutionary processes, to the sensory signals most likely to be received under ecologically relevant conditions. In order to conduct the present study along this line, we first recorded movies with the help of two microcameras carried by cats exploring a natural environment. This resulted in a database of binocular natural movies that was used in our theoretical and experimental studies. In a theoretical study, we aimed to understand the principles of binocular disparity encoding in terms of spatio-temporal statistical properties of natural movies in conjunction with simple mathematical expressions governing the activity levels of simulated neurons. In an unsupervised learning scheme, we used the binocular movies as input to a neuronal network and obtained receptive fields that represent these movies optimally with respect to the temporal stability criterion. Many distinctive aspects of the binocular coding in complex cells, such as the phase and position encoding of disparity and the existence of unbalanced ocular contributions, were seen to emerge as the result of this optimization process. Therefore we conclude that the encoding of binocular disparity by complex cells can be understood in terms of an optimization process that regulates activities of neurons receiving ecologically relevant information. Next we aimed to physiologically characterize the responses of the visual cortex to ecologically relevant stimuli in its full complexity and compare these to the responses evoked by artificial, conventional laboratory stimuli. To achieve this, a state-of-the-art recording method, voltage-sensitive dye imaging was used. This method captures the spatio-temporal activity patterns within the millisecond range across large cortical portions spanning over many pinwheels and orientation columns. It is therefore very well suited to provide a faithful picture of the cortical state in its full complexity. Drifting bar stimuli evoked two major sets of components, one coding for the position and the other for the orientation of the grating. Responses to natural stimuli involved more complex dynamics, which were locked to the motion present in the natural movies. In response to drifting gratings, the cortical state was initially dominated by a strong excitatory wave. This initial spatially widespread hyper-excitatory state had a detrimental effect on feature selectivity. In contrast, natural movies only rarely induced such high activity levels and the onset of inhibition cut short a further increase in activation level. An increase of 30% of the movie contrast was estimated to be necessary in order to produce activity levels comparable to gratings. These results show that the operating regime within which the natural movies are processed differs remarkably. Moreover, it remains to be established to what extent the cortical state under artificial conditions represents a valid state to make inferences concerning operationally more relevant input. The primary visual cortex contains a dense web of neuronal connections linking distant neurons. However the flow of information within this local network is to a large extent unknown under natural stimulation conditions. To functionally characterize these long-range intra-areal interactions, we presented natural movies also locally through either one or two apertures and analyzed the effects of the distant visual stimulation on the local activity levels. The distant patch had a net facilitatory effect on the local activity levels. Furthermore, the degree of the facilitation was dependent on the congruency between the two simultaneously presented movie patches. Taken together, our results indicate that the ecologically relevant stimuli are processed within a distinct operating regime characterized by moderate levels of excitation and/or high levels of inhibition, where facilitatory cooperative interactions form the basis of integrative processes. To gather better insights into the motion locking phenomenon and test the generalizability of the local cooperative processes toward larger scale interactions, we resorted to the unequalized temporal resolution of EEG and conducted a multimodal study. Inspired from the temporal properties of our natural movies, we designed a dynamic multimodal stimulus that was either congruent or incongruent across visual and auditory modalities. In the visual areas, the dynamic stimulation unfolded neuronal oscillations with frequencies well above the frequency spectrum content of the stimuli and the strength of these oscillations was coupled to the stimuli's motion profile. Furthermore, the coupling was found to be stronger in the case where the auditory and visual streams were congruent. These results show that the motion locking, which was so far observed in cats, is a phenomenon that also exists in humans. Moreover, the presence of long-range multimodal interactions indicates that, in addition to local intra-areal mechanisms ensuring the integration of local information, the central nervous system embodies an architecture that enables also the integration of information on much larger scales spread across different modalities. Any characterization of integrative phenomena at the neuronal level needs to be supplemented by its effects at the behavioral level. We therefore tested whether we could find any evidence of integration of different sources of information at the behavioral level using natural stimuli. To this end, we presented to human subjects images of natural scenes and evaluated the effect of simultaneously played localized natural sounds on their eye movements. The behavior during multimodal conditions was well approximated by a linear combination of the behavior under unimodal conditions. This is a strong indication that both streams of information are integrated in a joint multimodal saliency map before the final motor command is produced. The results presented here validate the possibility and the utility of using natural stimuli in experimental settings. It is clear that the ecological relevance of the experimental conditions are crucial in order to elucidate complex neuronal mechanisms resulting from evolutionary processes. In the future, having better insights on the nervous system can only be possible when the complexity of our experiments will match to the complexity of the mechanisms we are interested in.
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Nortmann, Nora. "Context Effects in Early Visual Processing and Eye Movement Control." Doctoral thesis, 2015. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2015042913187.

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There is a difference between the raw sensory input to the brain and our stable perception of entities in the environment. A first approach to investigate perception is to study relationships between properties of currently presented stimuli and biological correlates of perceptual processes. However, it is known that such processes are not only dependent on the current stimulus. Sampling of information and the concurrent neuronal processing of stimulus content rely on contextual relationships in the environment, and between the environment and the body. Perceptual processes dynamically adjust to relevant context, such as the current task of the organism and its immediate history. To understand perception, we have to study how processing of current stimulus content is influenced by such contextual factors. This thesis investigates the influence of such factors on visual processing. In particular, it investigates effects of temporal context in early visual processing and the effect of task context in eye movement control. To investigate effects of contextual factors on early visual processing of current stimulus content, we study neuronal processing of visual information in the primary visual cortex. We use real-time optical imaging with voltage sensitive dyes to capture neuronal population activity in the millisecond range across several millimeters of cortical area. To characterize the cortical layout concerning the mapping of orientation, previous to further investigations, we use smoothly moving grating stimuli. Investigating responses to this stimulus type systematically, we find independent encoding of local contrast and orientation, and a direct mapping of current stimulus content onto cortical activity (Study 1). To investigate the influence of the previous stimulus as context on processing of current stimulus content, we use abrupt visual changes in sequences of modified natural images. In earlier studies, investigating relatively fast timescales, it was found that the primary visual cortex continuously represents current input (ongoing encoding), with little interference from past stimuli. We investigate whether this coding scheme generalizes to cases in which stimuli change more slowly, as frequently encountered in natural visual input. We use sequences of natural scene contours, comprised of vertically and horizontally filtered natural images, their superpositions, and a blank stimulus, presented with 10 or 33 Hz. We show that at the low temporal frequency, cortical activity patterns do not encode the present orientations but instead reflect their relative changes in time. For example, when a stimulus with horizontal orientation is followed by the superposition of both orientations, the pattern of cortical activity represents the newly added vertical orientations instead of the full sum of orientations. Correspondingly, contour removal from the superposition leads to the representation of orientations that have disappeared rather than those that remain. This is in sharp contrast to more rapid sequences for which we find an ongoing representation of present input, consistent with earlier studies. In summary, we find that for slow stimulus sequences, populations of neurons in the primary visual cortex are no longer tuned to orientations within individual stimuli but instead represent the difference between consecutive stimuli. Our results emphasize the influence of the temporal context on early visual processing and consequentially on information transmission to higher cortical areas (Study 2). To study effects of contextual factors on the sampling of visual information, we focus on human eye movement control. The eyes are actively moved to sample visual information from the environment. Some traditional approaches predict eye movements solely on simple stimulus properties, such as local contrasts (stimulus-driven factors). Recent arguments, however, emphasize the influence of tasks (task context) and bodily factors (spatial bias). To investigate how contextual factors affect eye movement control, we quantify the relative influences of the task context, spatial biases and stimulus-driven factors. Participants view and classify natural scenery and faces while their eye movements are recorded. The stimuli are composed of small image patches. For each of these patches we derive a measure that quantifies stimulus-driven factors, based on the image content of a patch, and spatial viewing biases, based on the location of the patch. Utilizing the participants’ classification responses, we additionally derive a measure, which reflects the information content of a patch in the context of a given task. We show that the effect of spatial biases is highest, that task context is a close runner-up, and that stimulus-driven factors have, on average, a smaller influence. Remarkably, all three factors make independent and significant contributions to the selection of viewed locations. Hence, in addition to stimulus-driven factors and spatial biases, the task context contributes to visual sampling behavior and has to be considered in a model of human eye movements. Visual processing of current stimulus content, in particular visual sampling behavior and early processing, is inherently dependent on context. We show that already in the first cortical stage, temporal context strongly affects the processing of new visual information and that visual sampling by eye movements is significantly influenced by the task context, independently of spatial factors and stimulus-driven factors. The empirical results presented provide foundations for an improved theoretical understanding of the role of context in perceptual processes.
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Частини книг з теми "Optical voltage imaging"

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Devonshire, Ian M., Ying Zheng, and Jason Berwick. "Voltage Sensitive Dye Imaging, Intrinsic Optical Signals." In Encyclopedia of Computational Neuroscience, 3144–47. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4614-6675-8_541.

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2

Devonshire, Ian M., Ying Zheng, and Jason Berwick. "Voltage-Sensitive Dye Imaging, Intrinsic Optical Signals." In Encyclopedia of Computational Neuroscience, 1–4. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4614-7320-6_541-1.

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3

Tsytsarev, Vassiliy, and Reha S. Erzurumlu. "Voltage-Sensitive Dye and Intrinsic Signal Optical Imaging." In Neurophotonics and Brain Mapping, 101–16. Boca Raton : Taylor & Francis, 2017.: CRC Press, 2017. http://dx.doi.org/10.1201/9781315373058-7.

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4

Rol, Per E., Xiaoying Huang, and Jian-Young Wu. "In Vivo Dynamics of the Visual Cortex Measured with Voltage Sensitive Dyes." In Imaging the Brain with Optical Methods, 177–221. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-1-4419-0452-2_9.

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5

Hiyoshi, Kanae, Narumi Fukuda, Asuka Shiraishi, and Sachiko Tsuda. "In Vivo Optical Detection of Membrane Potentials in the Cerebellum: Voltage Imaging of Zebrafish." In Neuromethods, 229–44. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2026-7_12.

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6

Zochowski, Michal, Lawrence Cohen, Chun Falk, and Matt Wachowiak. "Voltage-Sensitive and Calcium-Sensitive Dye Imaging of Activity." In In Vivo Optical Imaging of Brain Function. CRC Press, 2002. http://dx.doi.org/10.1201/9781420038491.ch1.

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"Voltage-Sensitive and Calcium-Sensitive Dye Imaging of Activity: Examples from the Olfactory Bulb." In In Vivo Optical Imaging of Brain Function, 17–36. CRC Press, 2002. http://dx.doi.org/10.1201/9781420038491-6.

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8

"Imaging the Brain in Action: Real-Time Voltage-Sensitive Dye Imaging of Sensorimotor Cortex of Awake Behaving Mice." In In Vivo Optical Imaging of Brain Function, 187–208. CRC Press, 2009. http://dx.doi.org/10.1201/9781420076851-10.

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9

Jancke, Dirk. "Optical Imaging With Voltage Sensors—Capturing TMS-Induced Neuronal Signals Using Light." In Handbook of Behavioral Neuroscience, 223–34. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-812028-6.00012-4.

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10

Plies, Erich. "Electron Optics of Low-Voltage Electron Beam Testing and Inspection. Part I: Simulation Tools ✶ ✶Reprinted from Advances in Optical and Electron Microscopy, vol. 13, 1994, 123–242." In Advances in Imaging and Electron Physics, 139–267. Elsevier, 2018. http://dx.doi.org/10.1016/bs.aiep.2017.12.001.

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Тези доповідей конференцій з теми "Optical voltage imaging"

1

Xiao, Sheng, Eric Lowet, Howard Gritton, Pierre Fabris, Jerome Mertz, and Xue Han. "Large-scale optical voltage imaging in behaving animals." In Neural Imaging and Sensing 2022, edited by Qingming Luo, Jun Ding, and Ling Fu. SPIE, 2022. http://dx.doi.org/10.1117/12.2609095.

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2

Zou, Xian, Zhiming Wu, Weiping Wang, Defu Yin, Guangrong Li, Yongqiang Sun, Yaping Wu, Xu Li, and Junyong Kang. "Optimized design of 4H-SiC UMOSFET for high breakdown voltage." In Conference on Optical Sensing and Imaging Technology, edited by Dong Liu, Xiangang Luo, Yadong Jiang, and Jin Lu. SPIE, 2020. http://dx.doi.org/10.1117/12.2580265.

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Leite, Marina S. "Imaging Open Circuit Voltage in Solar Cells with Nanoscale Resolution." In Optical Nanostructures and Advanced Materials for Photovoltaics. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/pv.2014.pth3c.2.

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4

Weber, Timothy D., Maria V. Moya, Michael N. Economo, and Jerome Mertz. "Multi-plane 3D optical voltage imaging using high-speed multi-Z confocal microscopy." In Neural Imaging and Sensing 2022, edited by Qingming Luo, Jun Ding, and Ling Fu. SPIE, 2022. http://dx.doi.org/10.1117/12.2607867.

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5

Li, Hongbo, Guoqing Zhang, Xingguo Cai, Zhizhong Guo, Wenbin Yu, and Guangyu Huo. "Research on small signal detection of optical voltage/current transformer." In ISPDI 2013 - Fifth International Symposium on Photoelectronic Detection and Imaging, edited by Yunjiang Rao. SPIE, 2013. http://dx.doi.org/10.1117/12.2035253.

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Van Toan, Nguyen, Suguru Sangu, Yoshisuke Ansai, and Takahito Ono. "Reversible low voltage electrowetting with SiO2 capillary window for optical imaging." In 2017 IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2017. http://dx.doi.org/10.1109/memsys.2017.7863670.

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Lin, Michael. "Visualizing Electrical Activity in Neural Systems Using a New Family of Fast Genetically Encoded Voltage Indicators." In Optical Molecular Probes, Imaging and Drug Delivery. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/omp.2015.jw2b.2.

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Li, Zhi, Yansong Li, and Jun Liu. "Reciprocal optical voltage sensor with rotating double-crystal structure based on Pockels effect." In 2021 International Conference of Optical Imaging and Measurement (ICOIM). IEEE, 2021. http://dx.doi.org/10.1109/icoim52180.2021.9524393.

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Tang, Qinggong, Vassiliy Tsytsarev, Chia-Pin Liang, Reha Erzurumlu, and Yu Chen. "In Vivo Voltage-Sensitive Dye Optical Functional Imaging of the Subcortical Brain." In CLEO: Science and Innovations. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/cleo_si.2014.sth5c.3.

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Ng, Yin S., William Lo, and Kenneth Wilsher. "Next Generation Laser Voltage Probing." In ISTFA 2008. ASM International, 2008. http://dx.doi.org/10.31399/asm.cp.istfa2008p0249.

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Abstract We present an overview of Ruby, the latest generation of backside optical laser voltage probing (LVP) tools [1, 2]. Carrying over from the previous generation of IDS2700 systems, Ruby is capable of measuring waveforms up to 15GHz at low core voltages 0.500V and below. Several new optical capabilities are incorporated; these include a solid immersion lens (SIL) for improved imaging resolution [3] and a polarization difference probing (PDP) optical platform [4] for phase modulation detection. New developments involve Jitter Mitigation, a scheme that allows measurements of jittery signals from circuits that are internally driven by the IC’s onboard Phase Locked Loop (PLL). Additional timing features include a Hardware Phase-Locked Loop (HWPLL) scheme for improved locking of the LVP’s Mode-Locked Laser (MLL) to the tester clock as well as a clockless scheme to improve the LVP’s usefulness and user friendliness. This paper presents these new capabilities and compares these with those of the previous generation of LVP systems [5, 6].
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