Journal articles: 'Optical voltage imaging'

1

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

2

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

4

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

9

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

11

Möller, Lars, Gudrun Holland, and Michael Laue. "Diagnostic Electron Microscopy of Viruses With Low-voltage Electron Microscopes." Journal of Histochemistry & Cytochemistry 68, no. 6 (May 21, 2020): 389–402. http://dx.doi.org/10.1369/0022155420929438.

Full text

Abstract:

Diagnostic electron microscopy is a useful technique for the identification of viruses associated with human, animal, or plant diseases. The size of virus structures requires a high optical resolution (i.e., about 1 nm), which, for a long time, was only provided by transmission electron microscopes operated at 60 kV and above. During the last decade, low-voltage electron microscopy has been improved and potentially provides an alternative to the use of high-voltage electron microscopy for diagnostic electron microscopy of viruses. Therefore, we have compared the imaging capabilities of three low-voltage electron microscopes, a scanning electron microscope equipped with a scanning transmission detector and two low-voltage transmission electron microscopes, operated at 25 kV, with the imaging capabilities of a high-voltage transmission electron microscope using different viruses in samples prepared by negative staining and ultrathin sectioning. All of the microscopes provided sufficient optical resolution for a recognition of the viruses tested. In ultrathin sections, ultrastructural details of virus genesis could be revealed. Speed of imaging was fast enough to allow rapid screening of diagnostic samples at a reasonable throughput. In summary, the results suggest that low-voltage microscopes are a suitable alternative to high-voltage transmission electron microscopes for diagnostic electron microscopy of viruses.

APA, Harvard, Vancouver, ISO, and other styles

12

Manno, Carlo, Lourdes Figueroa, Robert Fitts, and Eduardo Ríos. "Confocal imaging of transmembrane voltage by SEER of di-8-ANEPPS." Journal of General Physiology 141, no. 3 (February 25, 2013): 371–87. http://dx.doi.org/10.1085/jgp.201210936.

Full text

Abstract:

Imaging, optical mapping, and optical multisite recording of transmembrane potential (Vm) are essential for studying excitable cells and systems. The naphthylstyryl voltage-sensitive dyes, including di-8-ANEPPS, shift both their fluorescence excitation and emission spectra upon changes in Vm. Accordingly, they have been used for monitoring Vm in nonratioing and both emission and excitation ratioing modes. Their changes in fluorescence are usually much less than 10% per 100 mV. Conventional ratioing increases sensitivity to between 3 and 15% per 100 mV. Low sensitivity limits the value of these dyes, especially when imaged with low light systems like confocal scanners. Here we demonstrate the improvement afforded by shifted excitation and emission ratioing (SEER) as applied to imaging membrane potential in flexor digitorum brevis muscle fibers of adult mice. SEER—the ratioing of two images of fluorescence, obtained with different excitation wavelengths in different emission bands—was implemented in two commercial confocal systems. A conventional pinhole scanner, affording optimal setting of emission bands but less than ideal excitation wavelengths, achieved a sensitivity of up to 27% per 100 mV, nearly doubling the value found by conventional ratioing of the same data. A better pair of excitation lights should increase the sensitivity further, to 35% per 100 mV. The maximum acquisition rate with this system was 1 kHz. A fast “slit scanner” increased the effective rate to 8 kHz, but sensitivity was lower. In its high-sensitivity implementation, the technique demonstrated progressive deterioration of action potentials upon fatiguing tetani induced by stimulation patterns at >40 Hz, thereby identifying action potential decay as a contributor to fatigue onset. Using the fast implementation, we could image for the first time an action potential simultaneously at multiple locations along the t-tubule system. These images resolved the radially varying lag associated with propagation at a finite velocity.

APA, Harvard, Vancouver, ISO, and other styles

13

Zhou, Jing, and Duandan Liang. "Intelligent Matching of the Control Voltage of Delay Line Interferometers for Differential Phase Shift Keying-Modulated Optical Signals." Photonics 8, no. 10 (October 6, 2021): 428. http://dx.doi.org/10.3390/photonics8100428.

Full text

Abstract:

In optical communications, differential phase shift keying (DPSK) provides a desired modulation format that offers high tolerance to nonlinear effects in high-speed transmissions. A DPSK demodulator converts the phase-coded signal into an intensity-coded signal at receivers. One demodulation scheme is called balanced detection and is based on a tunable delay line interferometer (DLI). Demodulation performances are determined by the phase delay generated by the DLI, while the phase delay is controlled by a tunable driving voltage on the DLI device. However, a problem in the dynamic adjustment of the control voltage prevents the application of DPSK demodulators. The receivers need to scan the whole control voltage range of the DLI and find the control voltage that maximizes the demodulation performance, but the scan-based method needs to undergo a very long searching time. In our work, we found that the relation between DLI control voltages and demodulation performance can be predicted rapidly by a feedforward neural network (FNN). In this paper, we propose a new method to quickly locate the best DLI control voltage based on an FNN. We also verify the proposed method in simulations and telecommunication systems, and the results show that the proposed method can significantly improve the efficiency of resolving the best demodulation voltages.

APA, Harvard, Vancouver, ISO, and other styles

14

Burgstahler, Ralf, Heidi Koegel, Franz Rucker, David Tracey, Peter Grafe, and Christian Alzheimer. "Confocal ratiometric voltage imaging of cultured human keratinocytes reveals layer-specific responses to ATP." American Journal of Physiology-Cell Physiology 284, no. 4 (April 1, 2003): C944—C952. http://dx.doi.org/10.1152/ajpcell.00053.2002.

Full text

Abstract:

Recent evidence suggests that changes in membrane potential influence the proliferation and differentiation of keratinocytes. To further elucidate the role of changes in membrane potential for their biological fate, the electrical behavior of keratinocytes needs to be studied under complex conditions such as multilayered cultures. However, electrophysiological recordings from cells in the various layers of a complex culture would be extremely difficult. Given the high spatial resolution of confocal imaging and the availability of novel voltage-sensitive dyes, we combined these methods in an attempt to develop a viable alternative for recording membrane potentials in more complex tissue systems. As a first step, we used confocal ratiometric imaging of fluorescence resonance energy transfer (FRET)-based voltage-sensitive dyes. We then validated this approach by comparing the optically recorded voltage signals in HaCaT keratinocytes with the electrophysiological signals obtained by whole cell recordings of the same preparation. We demonstrate 1) that optical recordings allow precise multisite measurements of voltage changes evoked by the extracellular signaling molecules ATP and bradykinin and 2) that responsiveness to ATP differs in various layers of cultured keratinocytes.

APA, Harvard, Vancouver, ISO, and other styles

15

Knöpfel, Thomas, and Chenchen Song. "Optical voltage imaging in neurons: moving from technology development to practical tool." Nature Reviews Neuroscience 20, no. 12 (November 8, 2019): 719–27. http://dx.doi.org/10.1038/s41583-019-0231-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Raguet, Hugo, Cyril Monier, Luc Foubert, Isabelle Ferezou, Yves Fregnac, and Gabriel Peyré. "Spatially Structured Sparse Morphological Component Separation for voltage-sensitive dye optical imaging." Journal of Neuroscience Methods 257 (January 2016): 76–96. http://dx.doi.org/10.1016/j.jneumeth.2015.09.024.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Krans, J. M., and T. L. van Rooy. "A Miniature Low Voltage SEM with High Resolution." Microscopy and Microanalysis 5, S2 (August 1999): 322–23. http://dx.doi.org/10.1017/s1431927600014938.

Full text

Abstract:

Miniaturization of electron optical systems has gained much interest over the last decade [1,2]. In a scanning electron microscope, downscaling of the column dimensions is expected to allow for high resolution imaging at low electron beam voltage. Main advantages of low voltage imaging are lower penetration depth, increased secondary electron yield, less specimen charging and better topographic contrast [3].We have developed a miniature scanning electron microscope (SEM) with high resolution at low beam energies. The outer dimensions of the miniaturized SEM column are 25 mm diameter and 95 mm length, including conventional field emitter electron source module. The column prototype is shown in Fig. 1. The size reduction has been achieved by the exclusive implementation of electrostatic column components. Electron optical simulations indicate that the retarding objective lens of the miniature SEM allows for a probe resolution of 3 nm at 1 keV beam energy. The secondary electrons are collected at an internal scintillator detector.

APA, Harvard, Vancouver, ISO, and other styles

18

Tsutsui, Hidekazu. "3SBA-06 FRET sensing of transmembrane voltage(3SBA Cutting-edge optical imaging approach to neuroscience-From single molecule to in vivo-,Symposium)." Seibutsu Butsuri 53, supplement1-2 (2013): S102. http://dx.doi.org/10.2142/biophys.53.s102_4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Slovin, Hamutal, Amos Arieli, Rina Hildesheim, and Amiram Grinvald. "Long-Term Voltage-Sensitive Dye Imaging Reveals Cortical Dynamics in Behaving Monkeys." Journal of Neurophysiology 88, no. 6 (December 1, 2002): 3421–38. http://dx.doi.org/10.1152/jn.00194.2002.

Full text

Abstract:

A novel method of chronic optical imaging based on new voltage-sensitive dyes (VSDs) was developed to facilitate the explorations of the spatial and temporal patterns underlying higher cognitive functions in the neocortex of behaving monkeys. Using this system, we were able to explore cortical dynamics, with high spatial and temporal resolution, over period of ≤1 yr from the same patch of cortex. The visual cortices of trained macaques were stained one to three times a week, and immediately after each staining session, the monkey started to perform the behavioral task, while the primary and secondary visual areas (V1 and V2) were imaged with a fast optical imaging system. Long-term repeated VSD imaging (VSDI) from the same cortical area did not disrupt the normal cortical architecture as confirmed repeatedly by optical imaging based on intrinsic signals. The spatial patterns of functional maps obtained by VSDI were essentially identical to those obtained from the same patch of cortex by imaging based on intrinsic signals. On comparing the relative amplitudes of the evoked signals and differential map obtained using these two different imaging methodologies, we found that VSDI emphasizes subthreshold activity more than imaging based on intrinsic signals, that emphasized more spiking activity. The latency of the VSD-evoked response in V1 ranged from 46 to 68 ms in the different monkeys. The amplitude of the V2 response was only 20−60% of that in V1. As expected from the anatomy, the retinotopic responses to local visual stimuli spread laterally across the cortical surface at a spreading velocity of 0.15−0.19 m/s over a larger area than that expected by the classical magnification factor, reaching its maximal anisotropic spatial extent within ∼40 ms. We correlated the observed dynamics of cortical activation patterns with the monkey's saccadic eye movements and found that due to the slow offset of the cortical response relative to its onset, there was a short period of simultaneous activation of two distinct patches of cortex following a saccade to the visual stimulus. We also found that a saccade to a small stimulus was followed by direct transient activation of a cortical region in areas of V1 and V2, located retinotopically within the saccadic trajectory.

APA, Harvard, Vancouver, ISO, and other styles

20

Cowley, J. M. "Alternative approaches to ultra-high resolution imaging." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 650–51. http://dx.doi.org/10.1017/s0424820100087562.

Full text

Abstract:

By extrapolation of past experience, it would seem that the future of ultra-high resolution electron microscopy rests with the advances of electron optical engineering that are improving the instrumental stability of high voltage microscopes to achieve the theoretical resolutions of 1Å or better at 1MeV or higher energies. While these high voltage instruments will undoubtedly produce valuable results on chosen specimens, their general applicability has been questioned on the basis of the excessive radiation damage effects which may significantly modify the detailed structures of crystal defects within even the most radiation resistant materials in a period of a few seconds. Other considerations such as those of cost and convenience of use add to the inducement to consider seriously the possibilities for alternative approaches to the achievement of comparable resolutions.

APA, Harvard, Vancouver, ISO, and other styles

21

Sjulson, L., and G. Miesenbock. "Rational Optimization and Imaging In Vivo of a Genetically Encoded Optical Voltage Reporter." Journal of Neuroscience 28, no. 21 (May 21, 2008): 5582–93. http://dx.doi.org/10.1523/jneurosci.0055-08.2008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Brahami, Aaron, Hadas Levy, Efrat Zlotkin-Rivkin, Naomi Melamed-Book, Nataly Tal, Dmitry Lev, Talia Yeshua, Oleg Fedosyeyev, Benjamin Aroeti, and Aaron Lewis. "Live cell near-field optical imaging and voltage sensing with ultrasensitive force control." Optics Express 25, no. 11 (May 15, 2017): 12131. http://dx.doi.org/10.1364/oe.25.012131.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Sit, Yiu Fai, and Risto Miikkulainen. "A computational model of the signals in optical imaging with voltage-sensitive dyes." Neurocomputing 70, no. 10-12 (June 2007): 1853–57. http://dx.doi.org/10.1016/j.neucom.2006.10.089.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Mironov, Sergey F., Frederick J. Vetter, and Arkady M. Pertsov. "Fluorescence imaging of cardiac propagation: spectral properties and filtering of optical action potentials." American Journal of Physiology-Heart and Circulatory Physiology 291, no. 1 (July 2006): H327—H335. http://dx.doi.org/10.1152/ajpheart.01003.2005.

Full text

Abstract:

Fluorescence imaging using voltage-sensitive dyes is an important tool for studying electrical propagation in the heart. Yet, the low amplitude of the voltage-sensitive component in the fluorescence signal and high acquisition rates dictated by the rapid propagation of the excitation wave front make it difficult to achieve recordings with high signal-to-noise ratios. Although spatially and temporally filtering the acquired signals has become de facto one of the key elements of optical mapping, there is no consensus regarding their use. Here we characterize the spatiotemporal spectra of optically recorded action potentials and determine the distortion produced by conical filters of different sizes. On the basis of these findings, we formulate the criteria for rational selection of filter characteristics. We studied the evolution of the spatial spectra of the propagating wave front after epicardial point stimulation of the isolated, perfused right ventricular free wall of the pig heart stained with di-4-ANEPPS. We found that short-wavelength (<3 mm) spectral components represent primarily noise and surface features of the preparation (coronary vessels, fat, and connective tissue). The time domain of the optical action potential spectrum also lacks high-frequency components (>100 Hz). Both findings are consistent with the reported effect of intrinsic blurring caused by light scattering inside the myocardial wall. The absence of high-frequency spectral components allows the use of aggressive low-pass spatial and temporal filters without affecting the optical action potential morphology. We show examples where the signal-to-noise ratio increased up to 150 with <3% distortion. A generalization of our approach to the rational filter selection in various applications is discussed.

APA, Harvard, Vancouver, ISO, and other styles

25

Xiang, Boyang, Guiru Gu, Nagarajan Ramaswamyd, Christopher Drew, and Xuejun Lu. "Voltage-dependent extended shortwave infrared (e-SWIR) photodetection-band tuning utilizing the Moss–Burstein effect." Journal of Physics D: Applied Physics 56, no. 5 (December 29, 2022): 055101. http://dx.doi.org/10.1088/1361-6463/aca9da.

Full text

Abstract:

Abstract Extended shortwave infrared (e-SWIR) photodetectors and imaging focal plane arrays covering the wavelength beyond the conventional In0.53Ga0.47As cutoff wavelength of 1.65 micrometers (µm) can find numerous applications in infrared sensing and imaging. This paper reports voltage-tunable e-SWIR photodetectors based on the conventional gallium antimonide (GaSb) n–i–p and p–i–n homojunctions on GaSb substrates, which offer bias-dependent photodetection band tuning with a simple structure and high material crystal quality due to the perfect lattice matching on the substrates. Detection bands between the cutoff wavelengths of 1.7 µm and 1.9 µm can be tuned with a low reverse bias voltage of <0.1 volts (V). The mechanism of the voltage-dependent band-tuning was analyzed and attributed to the Moss–Burstein effect, which changes the electron and hole filling factors under different reverse bias voltages. This analysis agreed with the experimental data. The Moss–Burstein effect-induced voltage-dependent band-tuning mechanism can provide useful guidance for the designs of e-SWIR photodetectors.

APA, Harvard, Vancouver, ISO, and other styles

26

Azimi Hashemi, Negin, Amelie C. F. Bergs, Christina Schüler, Anna Rebecca Scheiwe, Wagner Steuer Costa, Maximilian Bach, Jana F. Liewald, and Alexander Gottschalk. "Rhodopsin-based voltage imaging tools for use in muscles and neurons of Caenorhabditis elegans." Proceedings of the National Academy of Sciences 116, no. 34 (August 1, 2019): 17051–60. http://dx.doi.org/10.1073/pnas.1902443116.

Full text

Abstract:

Genetically encoded voltage indicators (GEVIs) based on microbial rhodopsins utilize the voltage-sensitive fluorescence of all-trans retinal (ATR), while in electrochromic FRET (eFRET) sensors, donor fluorescence drops when the rhodopsin acts as depolarization-sensitive acceptor. In recent years, such tools have become widely used in mammalian cells but are less commonly used in invertebrate systems, mostly due to low fluorescence yields. We systematically assessed Arch(D95N), Archon, QuasAr, and the eFRET sensors MacQ-mCitrine and QuasAr-mOrange, in the nematode Caenorhabditis elegans. ATR-bearing rhodopsins reported on voltage changes in body wall muscles (BWMs), in the pharynx, the feeding organ [where Arch(D95N) showed approximately 128% ΔF/F increase per 100 mV], and in neurons, integrating circuit activity. ATR fluorescence is very dim, yet, using the retinal analog dimethylaminoretinal, it was boosted 250-fold. eFRET sensors provided sensitivities of 45 to 78% ΔF/F per 100 mV, induced by BWM action potentials, and in pharyngeal muscle, measured in simultaneous optical and sharp electrode recordings, MacQ-mCitrine showed approximately 20% ΔF/F per 100 mV. All sensors reported differences in muscle depolarization induced by a voltage-gated Ca2+-channel mutant. Optogenetically evoked de- or hyperpolarization of motor neurons increased or eliminated action potential activity and caused a rise or drop in BWM sensor fluorescence. Finally, we analyzed voltage dynamics across the entire pharynx, showing uniform depolarization but compartmentalized repolarization of anterior and posterior parts. Our work establishes all-optical, noninvasive electrophysiology in live, intact C. elegans.

APA, Harvard, Vancouver, ISO, and other styles

27

Zhao, Hongliang, Tengteng Li, Qingyan Li, Chengqi Ma, Jie Li, Chenglong Zheng, Yating Zhang, and Jianquan Yao. "Low operating voltage monolithic stacked perovskite photodetectors for imaging applications." Optical Materials Express 11, no. 4 (March 8, 2021): 1004. http://dx.doi.org/10.1364/ome.420656.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Ravikumar, V. K., G. Lim, J. M. Chin, K. L. Pey, and J. K. W. Yang. "Understanding spatial resolution of laser voltage imaging." Microelectronics Reliability 88-90 (September 2018): 255–61. http://dx.doi.org/10.1016/j.microrel.2018.07.051.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Roy, Debjit, Zehavit Shapira, and Shimon Weiss. "Membrane potential sensing: Material design and method development for single particle optical electrophysiology." Journal of Chemical Physics 156, no. 8 (February 28, 2022): 084201. http://dx.doi.org/10.1063/5.0076522.

Full text

Abstract:

We review the development of “single” nanoparticle-based inorganic and organic voltage sensors, which can eventually become a viable tool for “non-genetic optogenetics.” The voltage sensing is accomplished with optical imaging at the fast temporal response and high spatial resolutions in a large field of view. Inorganic voltage nanosensors utilize the Quantum Confined Stark Effect (QCSE) to sense local electric fields. Engineered nanoparticles achieve substantial single-particle voltage sensitivity (∼2% Δλ spectral Stark shift up to ∼30% ΔF/F per 160 mV) at room temperature due to enhanced charge separation. A dedicated home-built fluorescence microscope records spectrally resolved images to measure the QCSE induced spectral shift at the single-particle level. Biomaterial based surface ligands are designed and developed based on theoretical simulations. The hybrid nanobiomaterials satisfy anisotropic facet-selective coating, enabling effective compartmentalization beyond non-specific staining. Self-spiking- and patched-HEK293 cells and cortical neurons, when stained with hybrid nanobiomaterials, show clear photoluminescence intensity changes in response to membrane potential (MP) changes. Organic voltage nanosensors based on polystyrene beads and nanodisk technology utilize Fluorescence (Förster) Resonance Energy Transfer (FRET) to sense local electric fields. Voltage sensing FRET pairs achieve voltage sensitivity up to ∼35% ΔF/F per 120 mV in cultures. Non-invasive MP recording from individual targeted sites (synapses and spines) with nanodisks has been realized. However, both of these QCSE- and FRET-based voltage nanosensors yet need to reach the milestone of recording individual action potentials from individual targeted sites.

APA, Harvard, Vancouver, ISO, and other styles

30

Resendiz-Rodriguez, F., and A. G. R. Evans. "Voltage discharge of light sensors in CCD imaging devices." IEEE Electron Device Letters 7, no. 5 (May 1986): 306–7. http://dx.doi.org/10.1109/edl.1986.26382.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Nikolaev, Dmitrii M., Vladimir N. Mironov, Andrey A. Shtyrov, Iaroslav D. Kvashnin, Andrey S. Mereshchenko, Andrey V. Vasin, Maxim S. Panov, and Mikhail N. Ryazantsev. "Fluorescence Imaging of Cell Membrane Potential: From Relative Changes to Absolute Values." International Journal of Molecular Sciences 24, no. 3 (January 26, 2023): 2435. http://dx.doi.org/10.3390/ijms24032435.

Full text

Abstract:

Membrane potential is a fundamental property of biological cells. Changes in membrane potential characterize a vast number of vital biological processes, such as the activity of neurons and cardiomyocytes, tumorogenesis, cell-cycle progression, etc. A common strategy to record membrane potential changes that occur in the process of interest is to utilize organic dyes or genetically-encoded voltage indicators with voltage-dependent fluorescence. Sensors are introduced into target cells, and alterations of fluorescence intensity are recorded with optical methods. Techniques that allow recording relative changes of membrane potential and do not take into account fluorescence alterations due to factors other than membrane voltage are already widely used in modern biological and biomedical studies. Such techniques have been reviewed previously in many works. However, in order to investigate a number of processes, especially long-term processes, the measured signal must be corrected to exclude the contribution from voltage-independent factors or even absolute values of cell membrane potential have to be evaluated. Techniques that enable such measurements are the subject of this review.

APA, Harvard, Vancouver, ISO, and other styles

32

Salzberg, B. M., and A. L. Obaid. "Sub-Millisecond Time Resolved Imaging of Voltage Changes in Excitable Cells and Tissues Using Multiple Site Optical Recording of Transmembrane Voltage (Msortv) and Molecular Probes." Microscopy and Microanalysis 3, S2 (August 1997): 803–4. http://dx.doi.org/10.1017/s1431927600010904.

Full text

Abstract:

Molecular indicators of membrane potential may be used to obtain sub-millisecond time resolved images of transient changes in membrane voltage in a variety of biological systems. These probes are small amphipathic molecules having molecular weights of 400-500, and dimensions on the order of 10 Angstroms, which bind to, but do not cross cell membranes, and change either their absorbance or fluorescence in response to membrane voltage. These extrinsic optical signals depend linearly upon membrane potential, and the best of the dyes respond to a step change in voltage in less than 1.5 μsec at room temperature. The salient properties of fast potentiometric probes will be discussed, and the fidelity of optical recordings to transmembrane voltage changes will be considered.Since voltage changes in excitable cells take place on a time scale that is determined by the kinetics of conformational changes in membrane proteins, and by membrane electrical time constants, these changes tend to be very rapid, and resolving them requires imaging systems that are frequently orders of magnitude faster than usual video rates.

APA, Harvard, Vancouver, ISO, and other styles

33

Oertner, Thomas G., Sandra Single, and Alexander Borst. "Separation of voltage- and ligand-gated calcium influx in locust neurons by optical imaging." Neuroscience Letters 274, no. 2 (October 1999): 95–98. http://dx.doi.org/10.1016/s0304-3940(99)00694-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Hidekazu, T. "Electrophysiological properties and optical imaging of membrane voltage in the teleost corpus glomerulosum slice." Neuroscience Research 38 (2000): S84. http://dx.doi.org/10.1016/s0168-0102(00)81351-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Tsytsarev, Vassiliy, Kaushalya Premachandra, Daisuke Takeshita, and Sonya Bahar. "Imaging cortical electrical stimulation in vivo: fast intrinsic optical signal versus voltage-sensitive dyes." Optics Letters 33, no. 9 (April 30, 2008): 1032. http://dx.doi.org/10.1364/ol.33.001032.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Kuznetsov, Andrey, Vytautas P. Bindokas, Jeremy D. Marks, and Louis H. Philipson. "FRET-based voltage probes for confocal imaging: membrane potential oscillations throughout pancreatic islets." American Journal of Physiology-Cell Physiology 289, no. 1 (July 2005): C224—C229. http://dx.doi.org/10.1152/ajpcell.00004.2005.

Full text

Abstract:

Insulin secretion is dependent on coordinated pancreatic islet physiology. In the present study, we found a way to overcome the limitations of cellular electrophysiology to optically determine cell membrane potential ( Vm) throughout an islet by using a fast voltage optical dye pair. Using laser scanning confocal microscopy (LSCM), we observed fluorescence (Förster) resonance energy transfer (FRET) with the fluorescent donor N-(6-chloro-7-hydroxycoumarin-3-carbonyl)-dimyristoylphosphatidyl-ethanolamine and the acceptor bis-(1,3-diethylthiobarbiturate) trimethine oxonol in the plasma membrane of essentially every cell within an islet. The FRET signal was approximately linear from Vm −70 to +50 mV with a 2.5-fold change in amplitude. We evaluated the responses of islet cells to glucose and tetraethylammonium. Essentially, every responding cell in a mouse islet displayed similar time-dependent changes in Vm. When Vm was measured simultaneously with intracellular Ca2+, all active cells showed tight coupling of Vm to islet cell Ca2+ changes. Our findings indicate that FRET-based, voltage-sensitive dyes used in conjunction with LSCM imaging could be extremely useful in studies of excitation-secretion coupling in intact islets of Langerhans.

APA, Harvard, Vancouver, ISO, and other styles

37

Dix-Peek, RM, EE van Dyk, FJ Vorster, and CJ Pretorius. "Breakdown voltage mapping through voltage dependent ReBEL intensity imaging of multi-crystalline Si solar cells." Physica B: Condensed Matter 535 (April 2018): 63–66. http://dx.doi.org/10.1016/j.physb.2017.06.041.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Hosokawa, Toshiyuki, Masaki Ohta, Takeshi Saito, and Alan Fine. "Imaging spatio-temporal patterns of long-term potentiation in mouse hippocampus." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1432 (April 29, 2003): 689–93. http://dx.doi.org/10.1098/rstb.2002.1217.

Full text

Abstract:

Spatio-temporal patterns of neuronal activity before and after the induction of long-term potentiation in mouse hippocampal slices were studied using a real-time high-resolution optical recording system. After staining the slices with voltage-sensitive dye, transmitted light images and extracellular field potentials were recorded in response to stimuli applied to CA1 stratum radiatum. Optical and electrical signals in response to single test pulses were enhanced for at least 30 minutes after brief high-frequency stimulation at the same site. In two-pathway experiments, potentiation was restricted to the tetanized pathway. The optical signals demonstrated that both the amplitude and area of the synaptic response were increased, in patterns not predictable from the initial, pretetanus, pattern of activation. Optical signals will be useful for investigating spatio-temporal patterns of synaptic enhancement underlying information storage in the brain.

APA, Harvard, Vancouver, ISO, and other styles

39

Momose-Sato, Yoko, Yoshiko Honda, Hiroshi Sasaki, and Katsushige Sato. "Optical Imaging of Large-Scale Correlated Wave Activity in the Developing Rat CNS." Journal of Neurophysiology 94, no. 2 (August 2005): 1606–22. http://dx.doi.org/10.1152/jn.00044.2005.

Full text

Abstract:

Correlated neuronal activity plays a fundamental role in the development of the nervous system. Using a multiple-site optical recording technique with a fast voltage-sensitive dye, we previously reported a novel form of correlated activity in the chick embryo, which showed wide propagation throughout the CNS. In this study, we report that similar wave activity is generated in the embryonic rat CNS. Electrical stimulation applied to the cervical cord evoked wave activity that traveled over a wide region of the CNS including the medulla, pons, midbrain, diencephalon, and spinal cord. Small signals were also detected from the cerebellum and part of the cerebrum. Stimulation applied to the cranial nerves such as the trigeminal and vagus nerves evoked waves with similar patterns, indicating that the wave is triggered by external sensory inputs. This wave activity was inhibited by glutamate-, acetylcholine-, GABA- and glycine-receptor antagonists in addition to gap junction blockers such as octanol and 18β-glycyrrhetinic acid. In the immunohistochemical study, significant immunoreactivity of connexin26 and connexin32 was also observed. Wave activity detected with a voltage-sensitive dye was accompanied by a Ca2+-wave, indicating that it not only provides electrical synchrony but also biochemical signals associated with [Ca2+]i elevation. These characteristics of the wave activity are similar to those of the depolarization wave reported in the chick embryo, suggesting that the large-scale depolarization wave is globally generated across different species.

APA, Harvard, Vancouver, ISO, and other styles

40

Takashima, Ichiro, and Riichi Kajiwara. "Voltage-Sensitive Dye versus Intrinsic Signal Optical Imaging: Comparison of Tactile Responses in Primary and Secondary Somatosensory Cortices of Rats." Brain Sciences 11, no. 10 (September 29, 2021): 1294. http://dx.doi.org/10.3390/brainsci11101294.

Full text

Abstract:

Studies using functional magnetic resonance imaging assume that hemodynamic responses have roughly linear relationships with underlying neural activity. However, to accurately investigate the neurovascular transfer function and compare its variability across brain regions, it is necessary to obtain full-field imaging of both electrophysiological and hemodynamic responses under various stimulus conditions with superior spatiotemporal resolution. Optical imaging combined with voltage-sensitive dye (VSD) and intrinsic signals (IS) is a powerful tool to address this issue. We performed VSD and IS imaging in the primary (S1) and secondary (S2) somatosensory cortices of rats to obtain optical maps of whisker-evoked responses. There were characteristic differences in sensory responses between the S1 and S2 cortices: VSD imaging revealed more localized excitatory and stronger inhibitory neural activity in S1 than in S2. IS imaging revealed stronger metabolic responses in S1 than in S2. We calculated the degree of response to compare the sensory responses between cortical regions and found that the ratio of the degree of response of S2 to S1 was similar, irrespective of whether the ratio was determined by VSD or IS imaging. These results suggest that neurovascular coupling does not vary between the S1 and S2 cortices.

APA, Harvard, Vancouver, ISO, and other styles

41

Hill, Evan S., Caroline Moore-Kochlacs, Sunil K. Vasireddi, Terrence J. Sejnowski, and William N. Frost. "Validation of Independent Component Analysis for Rapid Spike Sorting of Optical Recording Data." Journal of Neurophysiology 104, no. 6 (December 2010): 3721–31. http://dx.doi.org/10.1152/jn.00691.2010.

Full text

Abstract:

Independent component analysis (ICA) is a technique that can be used to extract the source signals from sets of signal mixtures where the sources themselves are unknown. The analysis of optical recordings of invertebrate neuronal networks with fast voltage-sensitive dyes could benefit greatly from ICA. These experiments can generate hundreds of voltage traces containing both redundant and mixed recordings of action potentials originating from unknown numbers of neurons. ICA can be used as a method for converting such complex data sets into single-neuron traces, but its accuracy for doing so has never been empirically evaluated. Here, we tested the accuracy of ICA for such blind source separation by simultaneously performing sharp electrode intracellular recording and fast voltage-sensitive dye imaging of neurons located in the central ganglia of Tritonia diomedea and Aplysia californica, using a 464-element photodiode array. After running ICA on the optical data sets, we found that in 34 of 34 cases the intracellularly recorded action potentials corresponded 100% to the spiking activity of one of the independent components returned by ICA. We also show that ICA can accurately sort action potentials into single neuron traces from a series of optical data files obtained at different times from the same preparation, allowing one to monitor the network participation of large numbers of individually identifiable neurons over several recording episodes. Our validation of the accuracy of ICA for extracting the neural activity of many individual neurons from noisy, mixed, and redundant optical recording data sets should enable the use of this powerful large-scale imaging approach for studies of invertebrate and suitable vertebrate neuronal networks.

APA, Harvard, Vancouver, ISO, and other styles

42

Felisari, L., V. Grillo, F. Jabeen, S. Rubini, C. Menozzi, F. Rossi, and F. Martelli. "Imaging with low-voltage scanning transmission electron microscopy: A quantitative analysis." Ultramicroscopy 111, no. 8 (July 2011): 1018–28. http://dx.doi.org/10.1016/j.ultramic.2011.03.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Liao Mingjuan, 廖明娟, 李雷 Li Lei, 段晓礁 Duan Xiaojiao, 陈大兵 Chen Dabing, and 刘丰林 Liu Fenglin. "源平移扫描局部CT成像及其检测在役高压电缆." Acta Optica Sinica 42, no. 16 (2022): 1611002. http://dx.doi.org/10.3788/aos202242.1611002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Homma, R., and M. Tanifuji. "Real-time Optical Imaging of Cortical Activity with Voltage-sensitive Dyes in Macaque Area TE." Seibutsu Butsuri 41, supplement (2001): S149. http://dx.doi.org/10.2142/biophys.41.s149_1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Tsytsarev, Vassiliy, Elena Pumbo, Qinggong Tang, Chao-Wei Chen, Vyacheslav Kalchenko, and Yu Chen. "Study of the cortical representation of whisker frequency selectivity using voltage-sensitive dye optical imaging." IntraVital 5, no. 1 (January 2, 2016): e1142637. http://dx.doi.org/10.1080/21659087.2016.1142637.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

McBride, J. W., A. Balestrero, L. Ghezzi, G. Tribulato, and K. J. Cross. "Optical fiber imaging for high speed plasma motion diagnostics: Applied to low voltage circuit breakers." Review of Scientific Instruments 81, no. 5 (May 2010): 055109. http://dx.doi.org/10.1063/1.3428737.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Tsytsarev, Vassiliy, Daniel Pope, Elena Pumbo, Alexander Yablonskii, and Michael Hofmann. "Study of the cortical representation of whisker directional deflection using voltage-sensitive dye optical imaging." NeuroImage 53, no. 1 (October 2010): 233–38. http://dx.doi.org/10.1016/j.neuroimage.2010.06.022.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Schemann, Michael, Klaus Michel, Saskia Peters, Stephan C. Bischoff, and Michel Neunlist. "III. Imaging and the gastrointestinal tract: mapping the human enteric nervous system." American Journal of Physiology-Gastrointestinal and Liver Physiology 282, no. 6 (June 1, 2002): G919—G925. http://dx.doi.org/10.1152/ajpgi.00043.2002.

Full text

Abstract:

Monitoring membrane potentials by multisite optical recording techniques using voltage-sensitive dyes is ideal for direct analysis of network signaling. We applied this technology to monitor fast and slow excitability changes in the enteric nervous system and in hundreds of neurons simultaneously at cellular and subcellular resolution. This imaging technique presents a powerful tool to study activity patterns in enteric pathways and to assess differential activation of nerves in the gut to a number of stimuli that modulate neuronal activity directly or through synaptic mechanisms. The optical mapping made it possible to record from tissues such as human enteric nerves, which were, until now, inaccessible by other techniques.

APA, Harvard, Vancouver, ISO, and other styles

49

Linardatos, Dionysios, Anastasios Konstantinidis, Ioannis Valais, Konstantinos Ninos, Nektarios Kalyvas, Athanasios Bakas, Ioannis Kandarakis, George Fountos, and Christos Michail. "On the Optical Response of Tellurium Activated Zinc Selenide ZnSe:Te Single Crystal." Crystals 10, no. 11 (October 22, 2020): 961. http://dx.doi.org/10.3390/cryst10110961.

Full text

Abstract:

In this study, the light output of a zinc selenide activated with tellurium (ZnSe: Te) single crystal was measured for X-ray radiography applications. A cubic crystal (10 × 10 × 10 mm) was irradiated using X-rays with tube voltages from 50 to 130 kV. The resulting energy absorption efficiency, detective quantum efficiency, and absolute luminescence efficiency were compared to published data for equally sized GSO: Ce (gadolinium orthosilicate) and BGO (bismuth germanium oxide) crystals. The emitted light was examined to estimate the spectral compatibility with widely used optical sensors. Energy absorption efficiency and detective quantum efficiency of ZnSe: Te and BGO were found to be similar, within the X-ray energies in question. Light output of all three crystals showed a tendency to increase with increasing X-ray tube voltage, but ZnSe: Te stood at least 2 EU higher than the others. ZnSe: Te can be coupled effectively with certain complementary metal–oxide–semiconductors (CMOS), photocathodes, and charge-coupled-devices (CCD), as the effective luminescence efficiency results assert. These properties render the material suitable for various imaging applications, dual-energy arrays included.

APA, Harvard, Vancouver, ISO, and other styles

50

Ke, Xiaoxing, Carla Bittencourt, and Gustaaf Van Tendeloo. "Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials." Beilstein Journal of Nanotechnology 6 (July 16, 2015): 1541–57. http://dx.doi.org/10.3762/bjnano.6.158.

Full text

Abstract:

A major revolution for electron microscopy in the past decade is the introduction of aberration correction, which enables one to increase both the spatial resolution and the energy resolution to the optical limit. Aberration correction has contributed significantly to the imaging at low operating voltages. This is crucial for carbon-based nanomaterials which are sensitive to electron irradiation. The research of carbon nanomaterials and nanohybrids, in particular the fundamental understanding of defects and interfaces, can now be carried out in unprecedented detail by aberration-corrected transmission electron microscopy (AC-TEM). This review discusses new possibilities and limits of AC-TEM at low voltage, including the structural imaging at atomic resolution, in three dimensions and spectroscopic investigation of chemistry and bonding. In situ TEM of carbon-based nanomaterials is discussed and illustrated through recent reports with particular emphasis on the underlying physics of interactions between electrons and carbon atoms.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Optical voltage imaging'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles