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Xia F, Rimoli CV, Akemann W, Ventalon C, Bourdieu L, Gigan S, de Aguiar HB. Neurophotonics beyond the surface: unmasking the brain's complexity exploiting optical scattering. NEUROPHOTONICS 2024; 11:S11510. [PMID: 38617592 PMCID: PMC11014413 DOI: 10.1117/1.nph.11.s1.s11510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 03/07/2024] [Accepted: 03/14/2024] [Indexed: 04/16/2024]
Abstract
The intricate nature of the brain necessitates the application of advanced probing techniques to comprehensively study and understand its working mechanisms. Neurophotonics offers minimally invasive methods to probe the brain using optics at cellular and even molecular levels. However, multiple challenges persist, especially concerning imaging depth, field of view, speed, and biocompatibility. A major hindrance to solving these challenges in optics is the scattering nature of the brain. This perspective highlights the potential of complex media optics, a specialized area of study focused on light propagation in materials with intricate heterogeneous optical properties, in advancing and improving neuronal readouts for structural imaging and optical recordings of neuronal activity. Key strategies include wavefront shaping techniques and computational imaging and sensing techniques that exploit scattering properties for enhanced performance. We discuss the potential merger of the two fields as well as potential challenges and perspectives toward longer term in vivo applications.
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Affiliation(s)
- Fei Xia
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
| | - Caio Vaz Rimoli
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Walther Akemann
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Cathie Ventalon
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Laurent Bourdieu
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Sylvain Gigan
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
| | - Hilton B. de Aguiar
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
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Rimoli CV, Moretti C, Soldevila F, Brémont E, Ventalon C, Gigan S. Demixing fluorescence time traces transmitted by multimode fibers. Nat Commun 2024; 15:6286. [PMID: 39060262 PMCID: PMC11282286 DOI: 10.1038/s41467-024-50306-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 07/05/2024] [Indexed: 07/28/2024] Open
Abstract
Optical methods based on thin multimode fibers (MMFs) are promising tools for measuring neuronal activity in deep brain regions of freely moving mice thanks to their small diameter. However, current methods are limited: while fiber photometry provides only ensemble activity, imaging techniques using of long multimode fibers are very sensitive to bending and have not been applied to unrestrained rodents yet. Here, we demonstrate the fundamentals of a new approach using a short MMF coupled to a miniscope. In proof-of-principle in vitro experiments, we disentangled spatio-temporal fluorescence signals from multiple fluorescent sources transmitted by a thin (200 µm) and short (8 mm) MMF, using a general unconstrained non-negative matrix factorization algorithm directly on the raw video data. Furthermore, we show that low-cost open-source miniscopes have sufficient sensitivity to image the same fluorescence patterns seen in our proof-of-principle experiment, suggesting a new avenue for novel minimally invasive deep brain studies using multimode fibers in freely behaving mice.
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Affiliation(s)
- Caio Vaz Rimoli
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, Paris, F-75005, France
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Claudio Moretti
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, Paris, F-75005, France
| | - Fernando Soldevila
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, Paris, F-75005, France
| | - Enora Brémont
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Cathie Ventalon
- Institut de Biologie de l'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France.
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, Paris, F-75005, France.
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Sarafraz H, Nöbauer T, Kim H, Soldevila F, Gigan S, Vaziri A. Speckle-enabled in vivo demixing of neural activity in the mouse brain. BIOMEDICAL OPTICS EXPRESS 2024; 15:3586-3608. [PMID: 38867774 PMCID: PMC11166431 DOI: 10.1364/boe.524521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/11/2024] [Accepted: 04/14/2024] [Indexed: 06/14/2024]
Abstract
Functional imaging of neuronal activity in awake animals, using a combination of fluorescent reporters of neuronal activity and various types of microscopy modalities, has become an indispensable tool in neuroscience. While various imaging modalities based on one-photon (1P) excitation and parallel (camera-based) acquisition have been successfully used for imaging more transparent samples, when imaging mammalian brain tissue, due to their scattering properties, two-photon (2P) microscopy systems are necessary. In 2P microscopy, the longer excitation wavelengths reduce the amount of scattering while the diffraction-limited 3D localization of excitation largely eliminates out-of-focus fluorescence. However, this comes at the cost of time-consuming serial scanning of the excitation spot and more complex and expensive instrumentation. Thus, functional 1P imaging modalities that can be used beyond the most transparent specimen are highly desirable. Here, we transform light scattering from an obstacle into a tool. We use speckles with their unique patterns and contrast, formed when fluorescence from individual neurons propagates through rodent cortical tissue, to encode neuronal activity. Spatiotemporal demixing of these patterns then enables functional recording of neuronal activity from a group of discriminable sources. For the first time, we provide an experimental, in vivo characterization of speckle generation, speckle imaging and speckle-assisted demixing of neuronal activity signals in the scattering mammalian brain tissue. We found that despite an initial fast speckle decorrelation, substantial correlation was maintained over minute-long timescales that contributed to our ability to demix temporal activity traces in the mouse brain in vivo. Informed by in vivo quantifications of speckle patterns from single and multiple neurons excited using 2P scanning excitation, we recorded and demixed activity from several sources excited using 1P oblique illumination. In our proof-of-principle experiments, we demonstrate in vivo speckle-assisted demixing of functional signals from groups of sources in a depth range of 220-320 µm in mouse cortex, limited by available speckle contrast. Our results serve as a basis for designing an in vivo functional speckle imaging modality and for maximizing the key resource in any such modality, the speckle contrast. We anticipate that our results will provide critical quantitative guidance to the community for designing techniques that overcome light scattering as a fundamental limitation in bioimaging.
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Affiliation(s)
- Hossein Sarafraz
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
| | - Tobias Nöbauer
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
- The Kavli Neural Systems Institute, The Rockefeller University, New York, NY, USA
| | - Hyewon Kim
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
| | - Fernando Soldevila
- Laboratoire Kastler Brossel, ENS–Université PSL, CNRS, Sorbonne Université, College de France, 24 Rue Lhomond, F-75005 Paris, France
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, ENS–Université PSL, CNRS, Sorbonne Université, College de France, 24 Rue Lhomond, F-75005 Paris, France
| | - Alipasha Vaziri
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
- The Kavli Neural Systems Institute, The Rockefeller University, New York, NY, USA
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Xia F, Rimoli CV, Akemann W, Ventalon C, Bourdieu L, Gigan S, de Aguiar HB. Neurophotonics beyond the Surface: Unmasking the Brain's Complexity Exploiting Optical Scattering. ARXIV 2024:arXiv:2403.14809v1. [PMID: 38562443 PMCID: PMC10984001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The intricate nature of the brain necessitates the application of advanced probing techniques to comprehensively study and understand its working mechanisms. Neurophotonics offers minimally invasive methods to probe the brain using optics at cellular and even molecular levels. However, multiple challenges persist, especially concerning imaging depth, field of view, speed, and biocompatibility. A major hindrance to solving these challenges in optics is the scattering nature of the brain. This perspective highlights the potential of complex media optics, a specialized area of study focused on light propagation in materials with intricate heterogeneous optical properties, in advancing and improving neuronal readouts for structural imaging and optical recordings of neuronal activity. Key strategies include wavefront shaping techniques and computational imaging and sensing techniques that exploit scattering properties for enhanced performance. We discuss the potential merger of the two fields as well as potential challenges and perspectives toward longer term in vivo applications.
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Affiliation(s)
- Fei Xia
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Caio Vaz Rimoli
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Walther Akemann
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Cathie Ventalon
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Laurent Bourdieu
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Hilton B de Aguiar
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
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Zhao S, Rauer B, Valzania L, Dong J, Liu R, Li F, Gigan S, de Aguiar HB. Single-pixel transmission matrix recovery via two-photon fluorescence. SCIENCE ADVANCES 2024; 10:eadi3442. [PMID: 38232161 DOI: 10.1126/sciadv.adi3442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 12/19/2023] [Indexed: 01/19/2024]
Abstract
Imaging at depth in opaque materials has long been a challenge. Recently, wavefront shaping has enabled notable advance for deep imaging. Nevertheless, most noninvasive wavefront-shaping methods require cameras, lack the sensitivity for deep imaging under weak optical signals, or can only focus on a single "guidestar." Here, we retrieve the transmission matrix (TM) noninvasively using two-photon fluorescence exploiting a single-pixel detection combined with a computational framework, allowing to achieve single-target focus on multiple guidestars spread beyond the memory effect range. In addition, if we assume that memory effect correlations exist in the TM, we are able to substantially reduce the number of measurements needed.
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Affiliation(s)
- Shupeng Zhao
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France. 24 rue Lhomond, 75005 Paris, France
- Shaanxi Province Key Laboratory for Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Bernhard Rauer
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France. 24 rue Lhomond, 75005 Paris, France
| | - Lorenzo Valzania
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France. 24 rue Lhomond, 75005 Paris, France
| | - Jonathan Dong
- Biomedical Imaging Group, Ecole polytechnique fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Ruifeng Liu
- Shaanxi Province Key Laboratory for Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Fuli Li
- Shaanxi Province Key Laboratory for Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France. 24 rue Lhomond, 75005 Paris, France
| | - Hilton B de Aguiar
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France. 24 rue Lhomond, 75005 Paris, France
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Soldevila F, Moretti C, Nöbauer T, Sarafraz H, Vaziri A, Gigan S. Functional imaging through scattering medium via fluorescence speckle demixing and localization. OPTICS EXPRESS 2023; 31:21107-21117. [PMID: 37381218 PMCID: PMC10316750 DOI: 10.1364/oe.487768] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/04/2023] [Accepted: 05/28/2023] [Indexed: 06/30/2023]
Abstract
Recently, fluorescence-based optical techniques have emerged as a powerful tool to probe information in the mammalian brain. However, tissue heterogeneities prevent clear imaging of deep neuron bodies due to light scattering. While several up-to-date approaches based on ballistic light allow to retrieve information at shallow depths inside the brain, non-invasive localization and functional imaging at depth still remains a challenge. It was recently shown that functional signals from time-varying fluorescent emitters located behind scattering samples could be retrieved by using a matrix factorization algorithm. Here we show that the seemingly information-less, low-contrast fluorescent speckle patterns recovered by the algorithm can be used to locate each individual emitter, even in the presence of background fluorescence. We test our approach by imaging the temporal activity of large groups of fluorescent sources behind different scattering phantoms mimicking biological tissues, and through a brain slice with a thickness of ∼200 µm.
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Affiliation(s)
- F. Soldevila
- Laboratoire Kastler Brossel, ENS–Université PSL, CNRS, Sorbonne Université, College de France, 24 Rue Lhomond, F-75005 Paris, France
| | - C. Moretti
- Laboratoire Kastler Brossel, ENS–Université PSL, CNRS, Sorbonne Université, College de France, 24 Rue Lhomond, F-75005 Paris, France
| | - T. Nöbauer
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
| | - H. Sarafraz
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
| | - A. Vaziri
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
- The Kavli Neural Systems Institute, The Rockefeller University, New York, NY, USA
| | - S. Gigan
- Laboratoire Kastler Brossel, ENS–Université PSL, CNRS, Sorbonne Université, College de France, 24 Rue Lhomond, F-75005 Paris, France
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