Optical Recording Research Articles

Discerning TGF and Leader Current Pulse in ASIM Observation

AbstractTerrestrial gamma ray flash (TGF) observations made by the Atmosphere‐Space Interaction Monitor (ASIM) have demonstrated that these TGFs are accompanied by a prominent optical pulse from a hot leader channel. It is hard to confidently resolve the true sequence of the events in the source region due to temporal proximity of the involved processes. Here we report a bright long duration TGF together with its associated optical recordings showing clear temporal separation between the TGF and the optical pulse. In this observation the optical pulse is clearly distinct and subsequent relative to the TGF. The corresponding lightning discharge occurred at the very end of the TGF. We conclude that the current surge inside the lightning leader channel cannot be responsible for generation of this TGF. The current surge that produced the associated optical pulse can itself be conditioned by the TGF and may be responsible for the TGF termination.

Multifunctional Neural Probes Enable Bidirectional Electrical, Optical, and Chemical Recording and Stimulation In Vivo.

Recording and modulation of neuronal activity enables the study of brain function in health and disease. While translational neuroscience relies on electrical recording and modulation techniques, mechanistic studies in rodent models leverage genetic precision of optical methods, such as optogenetics and fluorescent indicator imaging. In addition to electrical signal transduction, neurons produce and receive diverse chemical signals which motivate tools to probe and modulate neurochemistry. Although the past decade has delivered a wealth of technologies for electrophysiology, optogenetics, chemical sensing, and optical recording, combining these modalities within a single platform remains challenging. This work leverages materials selection and convergence fiber drawing to permit neural recording, electrical stimulation, optogenetics, fiber photometry, drug and gene delivery, and voltammetric recording of neurotransmitters within individual fibers. Composed of polymers and non-magnetic carbon-based conductors, these fibers are compatible with magnetic resonance imaging, enabling concurrent stimulation and whole-brain monitoring. Their utility is demonstrated in studies of the mesolimbic reward pathway by interfacing with the ventral tegmental area and nucleus accumbens in mice and characterizing the neurophysiological effects of a stimulant drug. This study highlights the potential of these fibers to probe electrical, optical, and chemical signaling across multiple brain regions in both mechanistic and translational studies.

All-Visible-Light-Activated Diarylethene Photoswitches.

Photochromic compounds have attracted much attention for their potential applications in photo-actuators, optoelectronic devices and optical recording techniques. This interest is driven by their key photochemical and photophysical properties, which can be reversibly modulated by light irradiation. Among them, diarylethene compounds have garnered extensive investigation due to their excellent thermal stability of both open- and closed-form isomers, robust fatigue resistance, high photocyclization quantum yield and good photochromic performance in both solution and solid phases. However, a notable limitation in expanding the utility of diarylethene compounds is the necessity for ultraviolet light to induce their photochromism. This requirement poses challenges, as ultraviolet light can be detrimental to biological tissues, and its penetration is often restricted in various media. This review provides an overview of design strategies employed in the development of visible-light-responsive diarylethene compounds. These design strategies serve as a guideline for molecular design, with the potential to significantly broaden the applications of all-visible-light-activated diarylethene compounds in the realms of materials science and biomedical science.

Optical Recording of Neuronal Activity in Brain Slices Stained with a Voltage-Sensitive Dye

Optical Recording of Neuronal Activity in Brain Slices Stained with a Voltage-Sensitive Dye

Optical Recording of Neuronal Activity in Brain Slices Stained with a Voltage-Sensitive Dye

Optical Recording of Neuronal Activity in Brain Slices Stained with a Voltage-Sensitive Dye

Recent Development of Chemigenetic Hybrid Voltage Indicators Enabled by Bioconjugation Chemistry.

Fluorescent voltage indicators enable the optical recording of electrophysiology across large cell populations with subcellular resolution; however, their application is often constrained by a limited photon budget. To address this limitation, advanced bioconjugation methods have been employed to site-specifically attach bright and photostable organic dyes to cell-specific protein scaffolds in live cells. The resulting chemigenetic hybrid voltage indicators enable sustained monitoring of voltage fluctuations with an exceptional signal-to-noise ratio, both in vitro and in vivo. This Viewpoint discusses recent advancements in the development of these indicators through bioconjugation chemistry.

Development and research testing of a low thrust on gaseous-propellant rocket engine chamber

The article presents preliminary results of the development and research testing of a rocket engine chamber with a thrust of 100 N operating on fuel components: gaseous oxygen-gaseous hydrogen, designed to be used as the main engine of a small upper stage for launching a payload weighing up to 150 kg into target orbits. The main features of the engine chamber are its fabrication by selective laser melting from 12X18N10T steel powder and its regenerative cooling with gaseous hydrogen. Calculation and experiments confirmed the possibility of regenerative cooling of the chamber in the nominal mode. In addition, the current results of the development of a technique for optical recording of the process of structural material removal from the chamber during tests using different optical filters are presented. It is shown that there is a correlation between the brightness of the obtained frames and the hydrogen flow rate. It is also shown that the afterburning of the removed material particles, in contrast to high thrust engines, occurs mainly in the tail of the jet.

High-resolution transcranial optical imaging of in vivo neural activity

Rapid sub-nanometer neuronal deformations have been shown to occur as a consequence of action potentials in vitro, allowing for optical registration of discrete axonal and synaptic depolarizations. Such optically-measured deformations are a novel signature for recording neural activity. We demonstrate this signature can be extended to in vivo measurements through recording of rapid neuronal deformations on the population level with holographic, optical phase-based recordings. Our system demonstrates, for the first time, non-invasive recordings of in vivo tissue deformation associated with population level neuronal activity, including through-skull. We confirmed this technique across a range of neural activation models, including direct epidural focal electrical stimulation, anesthetic-induced cortical deactivation, activation of primary somatosensory cortex via whisker barrel stimulation, and pharmacologically-induced seizures. Collectively, we show holographic imaging provides a pathway for high-resolution, label-free, non-invasive recording of transcranial in vivo neural activity at depth, making it highly advantageous for studying neural function and signaling.

Three-dimensional intelligent monitoring and early warning technology for tailings ponds based on spatiotemporal fusion of multisource big data.

To solve the difficult problems of tailings dam instability and environmental pollution, multisource information perception, prediction and early warning technology for tailings dams are investigated. Taking a tailings pond in China as an example, a three-dimensional visualization intelligent management platform based on the spatiotemporal fusion of multisource big data is established to realize intelligent real-time monitoring, prediction and early warning of tailings dams. A monitoring system for air-space-ground integration was developed via high-resolution optical image recording, unmanned aerial vehicles (UAVs), radar, video surveillance and displacement sensors. This approach can realize pollution monitoring and efficient identification of high-risk areas. In addition, a machine learning algorithm is used to mine spatiotemporal data in detail. The Alibaba cloud platform was adopted to develop a data integration framework. Multisensor spatiotemporal data from tailings dams and multisource monitoring data from the environment were integrated. The integrated management of tailings dam environmental monitoring, pollution and stability assessment is realized. A stability prediction model for tailings dams based on multisource data is proposed. The temporal and spatial information of various forms of data is analysed from multiple levels and perspectives. Rapid prediction of the disaster situation and stability of tailings ponds is realized. Moreover, a tailings pollution assessment model based on a neural network is integrated with multisource information to establish a multifactor environmental pollution neural network assessment model and a multilevel warning platform. This work can provide technical support for intelligent monitoring and early warning systems for tailings ponds.

Robust Carbon‐Dot Optical Disks for Orthogonal Amplitude‐Polarization Encryption Storage

AbstractHigh‐capacity steganography is crucial for the secure exchange of massive information. Exploring orthogonally optical recording can significantly improve encryption levels. However, due to the lack of robust media, the hidden data are easy to be cracked or destructed. Herein, carbon dots have the switchable memory function between optical transmittance and polarization state after receiving excitation power adjustment is discovered. A large‐area carbon‐based disk is further constructed which is measured to resist the high‐temperature damage at 423 K for more than 405 h and is estimated to remain stable at room‐temperature (301 K) beyond 2341 years. With the alternated arrangement of the dual functional carbon dots at one region of the disk, only by using an amplitude‐type holographic diffraction key can the polarized pattern be correctly read out. The ultra‐high secure encryption strategy also puts a bright way to the applications of 3D image hiding, permanent data preservation, and anti‐counterfeiting labels.

Effect of Spatial Resolution on Accurate Detection and Localization of Arrhythmia Rotors in Human Right Ventricular Tachycardia.

The goal of this study was to identify the spatial resolution requirements for accurate rotor detection and localization in human right ventricular tachyarrhythmias. Poor spatial resolution is often cited as a reason for the inaccuracy of cardiac mapping catheters in detecting and localizing arrhythmia rotors. High-resolution (0.7 mm) arrhythmia data from optical recordings obtained from human donor hearts (n = 12) were uniformly downsampled to lower resolutions (1.4-7 mm) to approximate the spatial resolution (4 mm) of clinical mapping catheters. Rotors were tracked at various subresolutions and compared to the rotors in the original data by computing F1-scores to create accuracy profiles for both rotor detection and localization. Further comparisons were made according to arrhythmia type, donor sex, anatomical region, and mapped surface: endocardium or epicardium. For a spatial resolution of 4.2 mm, the accuracies of rotor detection and localization were 57% ± 4% and 61% ± 7%, respectively. Arrhythmia type affected the accuracy of rotor detection (monomorphic ventricular tachycardia, 58% ± 4%; ventricular fibrillation, 56% ± 8%) and localization (monomorphic ventricular tachycardia, 70% ± 4%; ventricular fibrillation, 54% ± 13%). However, donor sex, anatomical region (right ventricular outflow tract, mid, and apical), and mapped surface (epicardium and endocardium) did not significantly affect rotor detection or localization accuracy. To achieve rotor detection accuracy of 80%, a spatial resolution of 1.4 mm or better is needed. The accuracy profiles provided here serve as a guideline for future mapping device development.

Методика перетворення кодових послідовностей у відповідності до системи координат модуляційного диска

An analysis of current approaches used in the design of optical recording systems for modulation disks has been conducted. By adapting mathematical models, software algo-rithms were developed to transform code sequences represented in polar, homogeneous, and parametric coordinate systems, and the unique characteristics of each approach in de-veloping a universal method for ensuring accurate and efficient modulation pattern trans-formation were established. It was noted that the polar coordinate system is the most suit-able for practical applications in code sequence transformations. Its ability to effectively represent circular and symmetrical structures, as well as the convenient representation of objects with radial symmetry, provides advantages in the creation of modulation disks. As a result of the study, effective software solutions for automating data processing in the formation of modulation patterns were identified. The implementation of the developed software algorithms for the presented approach involves adapting the code sequence to the current metric within the design of an optical system based on modulation disks. The pre-sented methodology ensures the ability to transform code sequences regardless of the cho-sen coordinate system, which significantly enhances its flexibility and versatility for prac-tical applications.

Magneto–Optical Properties and Applications of Magnetic Garnet

The interaction between light and the magnetization of a material is called the magneto–optical effect. It was used in magneto–optical recording such as MO disks and has been applied to optical isolators etc. with the development of optical communications. The magneto–optical properties of magnetic garnets and their applications are briefly reviewed in this article. In the first half, after a brief overview of the phenomenology of the magneto–optical effect, the effects of element substitution on properties such as Faraday rotation and optical absorbance of magnetic garnets are shown. In the second half, some interesting applications such as imaging technologies and other novel applications using the magneto–optical effect of magnetic garnets are also introduced.

Zona Incerta GABAergic Neurons Facilitate Emergence from Isoflurane Anesthesia in Mice.

The zona incerta (ZI) predominantly consists of gamma-aminobutyric acid (GABAergic) neurons, located adjacent to the lateral hypothalamus. GABA, acting on GABAA receptors, serves as a crucial neuromodulator in the initiation and maintenance of general anesthesia. In this study, we aimed to investigate the involvement of ZI GABAergic neurons in the general anesthesia process. Utilizing in-vivo calcium signal optical fiber recording, we observed a decrease in the activity of ZI GABAergic neurons during isoflurane anesthesia, followed by a significant increase during the recovery phase. Subsequently, we selectively ablated ZI GABAergic neurons to explore their role in general anesthesia, revealing no impact on the induction of isoflurane anesthesia but a prolonged recovery time, accompanied by a reduction in delta-band power in mice under isoflurane anesthesia. Finally, through optogenetic activation/inhibition of ZI GABAergic neurons during isoflurane anesthesia, we discovered that activation of these neurons facilitated emergence without affecting the induction process, while inhibition delayed emergence, leading to fluctuations in delta band activity. In summary, these findings highlight the involvement of ZI GABAergic neurons in modulating the emergence of isoflurane anesthesia.

Advantages of Direct Laser Writing for Enhancing the Resolution of Diffractive Optical Element Fabrication Processes

A technology for direct laser writing of code sequences on modulation disks has been developed and implemented, ensuring high accuracy and reliability in the process of forming structural elements. The main advantages of applying direct laser writing compared to contact lithography for forming submicron-sized elements have been demonstrated. The proposed technology is characterized by high resolution and flexibility in configuring the parameters of the optical recording system, making it suitable for a wide range of applications in micro-optics. Direct optical writing is presented as a promising approach for enhancing the resolution of optical systems used in recording submicron-sized diffractive optical elements, as this technology enables the creation of complex optical structures. Additionally, a detailed classification of current approaches for further increasing the resolution of the optical recording system was conducted, including the application of a saturated absorber layer on the photosensitive surface, the use of a laser beam with intensity modeled by a Bessel function, and the synthesis of photosensitive materials with optimized exposure characteristics, ensuring high efficiency and accuracy in the process of direct laser writing.

In vivo imaging of vagal-induced myenteric plexus responses in gastrointestinal tract with an optical window

The vagus nerve (VN) extensively innervates the gastric enteric nervous system (ENS), but its influence on gastric ENS functionality and motility in vivo remains unclear due to technical challenges. Here we describe a method for stable, long-term observation of gastric ENS activity and muscle dynamics at cellular resolution, which can also be extended to intestinal applications. This method involves ENS-specific labeling and the implantation of an abdominal wall window for optical recording in male mice. In vivo calcium imaging reveals a linear relationship between vagal stimulation frequency and myenteric neuron activation in gastric antrum. Furthermore, the motility of gastric antrum is significantly enhanced and shows a positive correlation with the intensity and number of activated myenteric neurons. While vagal stimulation also activates proximal colonic myenteric neurons, this activation is not frequency-dependent and does not induce proximal colonic motility. The method and results provide important insights into VN-ENS interactions in vivo, advancing our understanding of gastrointestinal motility regulation.

Dietary fat content and absorption shape standard diet devaluation through hunger circuits

ObjectiveExposure to 60% high fat diet (HFD) leads to a robust consummatory preference over well-balanced chow standard diet (SD) when mice are presented with a choice. This passive HFD-induced SD devaluation following HFD challenge and withdrawal is highlighted by the significant reduction in SD food intake even in states of caloric deprivation. The elements of HFD that lead to this SD depreciation remains unclear. Possibly important factors include the amount and type of fat contained in a diet as well as past eating experiences dependent on sensory properties including taste and post ingestive feedback. We aimed to explore the role of these components to HFD-induced SD devaluation. MethodsWildtype mice were longitudinally presented discrete HFDs in conjunction with SD and feeding and metabolic parameters were analyzed. A separate cohort of animals were assessed for acute HFD preference in 3 conditions: 1) ad libitum fed (sated), 2) overnight fasted (physiologically hungry), and 3) ad libitum fed (artificially hungry), elicited through chemogenetic Agouti-related peptide (AgRP) neuron activation. Population dynamics of AgRP neurons were recorded to distinct inaccessible and accessible diets both before and after consummatory experience. Transient receptor potential channel type M5 (TRPM5) knockout mice were used to investigate the role of fat taste perception and preference to HFD-induced SD devaluation. The clinically approved lipase inhibitor orlistat was used to test the contribution of fat absorption to HFD-induced SD devaluation. ResultsHFD-induced SD devaluation is dependent on fat content, composition, and preference. This effect scaled both in strength and latency with higher percentages of animal fat. 60% HFD was preferred and almost exclusively consumed in preference to other diets across hours and days, but this was not as evident upon initial introduction over seconds and minutes, suggesting ingestive experience is critical. Optical fiber photometry recordings of AgRP activity supported this notion as neuronal suppression by the different diets was contingent on prior intake. While taste transduced via TRPM5 influenced HFD-evoked weight gain, it failed to impact either HFD preference or HFD-induced SD devaluation. Perturbation of post ingestive feedback through orlistat-mediated diminishment of fat absorption prevented HFD-evoked weight gain and abolished HFD-induced SD devaluation. ConclusionsPost ingestive feedback via fat digestion is vital for expression of HFD-induced SD devaluation.

Top-down modulation of the retinal code via histaminergic neurons of the hypothalamus.

The mammalian retina is considered an autonomous circuit, yet work dating back to Ramon y Cajal indicates that it receives inputs from the brain. How such inputs affect retinal processing has remained unknown. We confirmed brain-to-retina projections of histaminergic neurons from the mouse hypothalamus. Histamine application ex vivo altered the activity of various retinal ganglion cells (RGCs), including direction-selective RGCs that gained responses to high motion velocities. These results were reproduced in vivo with optic tract recordings where histaminergic retinopetal axons were activated chemogenetically. Such changes could improve vision of fast-moving objects (e.g., while running), which fits with the known increased activity of histaminergic neurons during arousal. An antihistamine drug reduced optomotor responses to high-speed moving stimuli in freely moving mice. In humans, the same antihistamine nonuniformly modulated visual sensitivity across the visual field, indicating an evolutionary conserved function of the histaminergic system. Our findings expose a previously unappreciated role for brain-to-retina projections in modulating retinal function.

Rapid Generation of Birefringent Nanostructures by Spatially and Energy Manipulated Femtosecond Lasers for Ultra-High Speed 5D Optical Recording Exceeding MB/s

Rapid Generation of Birefringent Nanostructures by Spatially and Energy Manipulated Femtosecond Lasers for Ultra-High Speed 5D Optical Recording Exceeding MB/s

Results from the InSight atmospheric imaging campaign

NASA's InSight lander monitored the Martian atmosphere while conducting its primarily geophysical investigation. Atmospheric imaging was used to study dust and ice at the site for over two Mars years in 2018–2022. An optical depth record, including dust and ice, was derived from systematic sky imaging in the mornings (for the first part of the mission) and evenings. Optical depths ranged from 0.5 to 1.9 but were typically under 1. Dust storms were seen at expected times in late northern autumn and early winter, including one shortly after landing, along with one late summer storm in January 2022. The optical depth record closely matched that of Curiosity, 600 km to the south, except for the expected additional water ice content during the aphelion cloud belt (ACB, spring to early summer). In addition to ice hazes, the ACB included discrete clouds, whose motion was tracked to show northeasterly to southeasterly daytime winds. While InSight recorded many meteorological vortices, no dust devils were seen, requiring that dust-devil occurrence was <10−3 times as common as during Spirit rover dust devil seasons.