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Balasubramanian H, Hobson CM, Chew TL, Aaron JS. Imagining the future of optical microscopy: everything, everywhere, all at once. Commun Biol 2023; 6:1096. [PMID: 37898673 PMCID: PMC10613274 DOI: 10.1038/s42003-023-05468-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/16/2023] [Indexed: 10/30/2023] Open
Abstract
The optical microscope has revolutionized biology since at least the 17th Century. Since then, it has progressed from a largely observational tool to a powerful bioanalytical platform. However, realizing its full potential to study live specimens is hindered by a daunting array of technical challenges. Here, we delve into the current state of live imaging to explore the barriers that must be overcome and the possibilities that lie ahead. We venture to envision a future where we can visualize and study everything, everywhere, all at once - from the intricate inner workings of a single cell to the dynamic interplay across entire organisms, and a world where scientists could access the necessary microscopy technologies anywhere.
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Affiliation(s)
| | - Chad M Hobson
- Advanced Imaging Center; Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Teng-Leong Chew
- Advanced Imaging Center; Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA
| | - Jesse S Aaron
- Advanced Imaging Center; Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA.
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Pochechuev MS, Fedotov IV, Martynov GN, Solotenkov MA, Ivashkina OI, Rogozhnikova OS, Fedotov AB, Anokhin KV, Zheltikov AM. Implantable graded-index fibers for neural-dynamics-resolving brain imaging in awake mice on an air-lifted platform. JOURNAL OF BIOPHOTONICS 2022; 15:e202200025. [PMID: 35666011 DOI: 10.1002/jbio.202200025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/13/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate a versatile framework for cellular brain imaging in awake mice based on suitably tailored segments of graded-index (GRIN) fiber. Closed-form solutions to ray-path equations for graded-index waveguides are shown to offer important insights into image-transmission properties of GRIN fibers, suggesting useful recipes for optimized GRIN-fiber-based deep-brain imaging. We show that the lengths of GRIN imaging components intended for deep-brain studies in freely moving rodents need to be chosen as a tradeoff among the spatial resolution, the targeted imaging depth and the degree of fiber-probe invasiveness. In the experimental setting that we present in this paper, the head of an awake mouse with a GRIN-fiber implant is fixed under a microscope objective, but the mouse is free to move around an in-house-built flat-floored air-lifted platform, exploring a predesigned environment, configured as an arena for one of standard cognitive tests. We show that cellular-resolution deep-brain imaging can be integrated in this setting with robust cell-specific optical neural recording to enable in vivo studies with minimal physical restraints on animal models. The enhancement of the information capacity of the fluorescence signal, achieved via a suitable filtering of the GRIN-fiber readout, is shown to open routes toward practical imaging modalities whereby the deep-brain neuronal dynamics and axonal connections underpinning the integrative functions of essential brain structures can be studied in awake rodent models.
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Affiliation(s)
| | - Ilya V Fedotov
- Physics Department, M.V. Lomonosov Moscow State University, Moscow, Russia
- Department of Physics and Astronomy, IQSE, Texas A&M University, College Station, Texas, USA
- Russian Quantum Center, Skolkovo, Moscow, Russia
| | | | - Maxim A Solotenkov
- Physics Department, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Olga I Ivashkina
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, Moscow, Russia
- National Research Center "Kurchatov Institute", Moscow, Russia
- P.K. Anokhin Research Institute of Normal Physiology, Moscow, Russia
| | - Olga S Rogozhnikova
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Andrei B Fedotov
- Physics Department, M.V. Lomonosov Moscow State University, Moscow, Russia
- Russian Quantum Center, Skolkovo, Moscow, Russia
- National University of Science and Technology "MISiS,", Moscow, Russia
| | - Konstantin V Anokhin
- Institute for Advanced Brain Studies, M.V. Lomonosov Moscow State University, Moscow, Russia
- P.K. Anokhin Research Institute of Normal Physiology, Moscow, Russia
| | - Aleksei M Zheltikov
- Department of Physics and Astronomy, IQSE, Texas A&M University, College Station, Texas, USA
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Zheltikov AM. State-vector geometry and guided-wave physics behind optical super-resolution. OPTICS LETTERS 2022; 47:1586-1589. [PMID: 35363684 DOI: 10.1364/ol.441643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
We examine the state-vector geometry and guided-wave physics underpinning spatial super-resolution, which can be attained in far-field linear microscopy via a combination of statistical analysis, quantum optics, and spatial mode demultiplexing. A suitably tailored guided-wave signal pickup is shown to provide an information channel that can distill the super-resolving spatial modes, thus enabling an estimation of sub-Rayleigh space intervals ξ. We derive closed-form analytical expressions describing the distribution of the ξ-estimation Fisher information over waveguide modes, showing that this information remains nonvanishing as ξ → 0, thus preventing the variance of ξ estimation from diverging at ξ → 0. We demonstrate that the transverse refractive index profile nQ(r) tailored to support the optimal wave function ψQ(r) for super-resolving ξ estimation encodes the same information about ξ as the entire manifold of waveguide modes needed to represent ψQ(r). Unlike ψQ(r), nQ(r) does not need a representation in a lengthy manifold of eigenmodes and can be found instead via adaptive feedback-controlled learning.
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Schmidt CC, Turcotte R, Booth MJ, Emptage NJ. Repeated imaging through a multimode optical fiber using adaptive optics. BIOMEDICAL OPTICS EXPRESS 2022; 13:662-675. [PMID: 35284159 PMCID: PMC8884233 DOI: 10.1364/boe.448277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
Multimode optical fibers (MMF) have shown considerable potential for minimally invasive diffraction-limited fluorescence imaging of deep brain regions owing to their small size. They also look to be suitable for imaging across long time periods, with repeated measurements performed within the same brain region, which is useful to assess the role of synapses in normal brain function and neurological disease. However, the approach is not without challenge. Prior to imaging, light propagation through a MMF must be characterized in a calibration procedure. Manual repositioning, as required for repeated imaging, renders this calibration invalid. In this study, we provide a two-step solution to the problem consisting of (1) a custom headplate enabling precise reinsertion of the MMF implant achieving low-quality focusing and (2) sensorless adaptive optics to correct translational shifts in the MMF position enabling generation of high-quality imaging foci. We show that this approach achieves fluorescence imaging after repeated removal and reinsertion of a MMF.
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Affiliation(s)
- Carla C. Schmidt
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
- These authors contributed equally
| | - Raphaël Turcotte
- Tech4Health Institute, NYU Langone Health, New York, NY 10010, USA
- These authors contributed equally
| | - Martin J. Booth
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, United Kingdom
| | - Nigel J. Emptage
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
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Adaptive Wave-Front Shaping and Beam Focusing through Fiber Bundles for High-Resolution Bioimaging. PHOTONICS 2021. [DOI: 10.3390/photonics9010021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We demonstrate an adaptive wave-front shaping of optical beams transmitted through fiber bundles as a powerful resource for multisite, high-resolution bioimaging. With the phases of all the beamlets delivered through up to 6000 different fibers within the fiber bundle controlled individually, by means of a high-definition spatial light modulator, the overall beam transmitted through the fiber bundle can be focused into a beam waist with a diameter less than 1 μm within a targeted area in a biotissue, providing a diffraction-limited spatial resolution adequate for single-cell or even subcellular bioimaging. The field intensity in the adaptively-focused continuous-wave laser beam in our fiber-bundle-imaging setting is more than two orders of magnitude higher than the intensity of the speckle background. Once robust beam focusing was achieved with a suitable phase profile across the input face of the fiber bundle, the beam focus can be scanned over a targeted area with no need for a further adaptive search, by applying a physically intuitive, wave-front-tilting phase mask on the field of input beamlets. This method of beam-focus scanning promises imaging speeds compatible with the requirements of in vivo calcium imaging.
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Wang L, Ge C, Wang F, Guo Z, Hong W, Jiang C, Ji B, Wang M, Li C, Sun B, Liu J. Dense Packed Drivable Optrode Array for Precise Optical Stimulation and Neural Recording in Multiple-Brain Regions. ACS Sens 2021; 6:4126-4135. [PMID: 34779610 DOI: 10.1021/acssensors.1c01650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The input-output function of neural networks is complicated due to the huge number of neurons and synapses, and some high-density implantable electrophysiology recording tools with a plane structure have been developed for neural circuit studies in recent years. However, traditional plane probes are limited by the record-only function and inability to monitor multiple-brain regions simultaneously, and the complete cognition of neural networks still has a long way away. Herein, we develop a three-dimensional (3D) high-density drivable optrode array for multiple-brain recording and precise optical stimulation simultaneously. The optrode array contains four-layer probes with 1024 microelectrodes and two thinned optical fibers assembled into a 3D-printed drivable module. The recording performance of microelectrodes is optimized by electrochemical modification, and precise implantation depth control of drivable optrodes is verified in agar. Moreover, in vivo experiments indicate neural activities from CA1 and dentate gyrus regions are monitored, and a tracking of the neuron firing for 2 weeks is achieved. The suppression of neuron firing by blue light has been realized through high-density optrodes during optogenetics experiments. With the feature of large-scale recording, optoelectronic integration, and 3D assembly, the high-density drivable optrode array possesses an important value in the research of brain diseases and neural networks.
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Affiliation(s)
- Longchun Wang
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chaofan Ge
- Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Fang Wang
- Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200020, China
| | - Zhejun Guo
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wen Hong
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chunpeng Jiang
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bowen Ji
- Unmanned System Research Institute, Northwestern Polytechnical University, Xi’an 710072, China
| | - Minghao Wang
- College of Electronics and Information Hangzhou Dianzi University, Hangzhou 310018, China
| | - Chengyu Li
- Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bomin Sun
- Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200020, China
| | - Jingquan Liu
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, Shanghai 200240, China
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Zheltikov AM. Light-induced uncertainty and information limits of optical neural recording. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 251:119351. [PMID: 33486433 DOI: 10.1016/j.saa.2020.119351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
Cutting-edge methods of laser microscopy combined with fluorescent protein engineering and spectral analysis provide a unique resource for high-resolution neuroimaging, enabling a high-fidelity, high-contrast detection of fine structural details of neural cells and intracellular compartments. In addition to their extraordinary imaging abilities in real space, such methods can help resolve the neural states in a multidimensional space of neural responses whereby individual neurons and neural populations encode information on external stimuli. This study shows, however, that laser-induced biochemical processes in neural cells can give rise to an uncertainty of neural states, setting an upper bound on the information that optical measurements can provide on neural states, neural encodings, and neural dynamics. Comparison of absorbed laser power with the native biochemical energy budget of neuronal firing suggests that each readout photon in optical recording comes at a cost of precision of neural encoding and a loss of information encoded by the neural response. A quantitative measure for such a measurement-induced neural uncertainty can be defined, as this study shows, in terms of the Fisher information, relating the lower bound of this uncertainty to the loss of the Shannon information capacity of neural states.
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Affiliation(s)
- Aleksei M Zheltikov
- Physics Department, M.V. Lomonosov Moscow State University, Moscow 119992, Russia; Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA; Russian Quantum Center, Skolkovo, Moscow Region 143025, Russia; Kazan Quantum Center, A.N. Tupolev Kazan National Research Technical University, 420126 Kazan, Russia
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