Dr. Valentina Emiliani Profile

Dr. Valentina Emiliani

Lab Director at Lab de neurophysiologie et nouvelles microscopies

SPIE Involvement:

Editorial Board Member: Neurophotonics | Author

Publications (16)

SPIE Journal Paper | 4 April 2024 Open Access

Open Access

Blue-shifted genetically encoded Ca²⁺ indicator with enhanced two-photon absorption

Abhi Aggarwal, Smrithi Sunil, Imane Bendifallah, Michael Moon, Mikhail Drobizhev, Landon Zarowny, Jihong Zheng, Sheng-Yi Wu, Alexander Lohman, Alison Tebo, Valentina Emiliani, Kaspar Podgorski, Yi Shen, Robert Campbell

NPh, Vol. 11, Issue 02, 024207, (April 2024) https://doi.org/10.1117/12.10.1117/1.NPh.11.2.024207

KEYWORDS: Calcium, Fluorescence, Proteins, Action potentials, Signal to noise ratio, Photometry, Neurophotonics, Neurons, In vivo imaging, Chromophores

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SignificanceGenetically encoded calcium ion (Ca2+) indicators (GECIs) are powerful tools for monitoring intracellular Ca2+ concentration changes in living cells and model organisms. In particular, GECIs have found particular utility for monitoring the transient increase of Ca2+ concentration that is associated with the neuronal action potential. However, the palette of highly optimized GECIs for imaging of neuronal activity remains relatively limited. Expanding the selection of available GECIs to include new colors and distinct photophysical properties could create new opportunities for in vitro and in vivo fluorescence imaging of neuronal activity. In particular, blue-shifted variants of GECIs are expected to have enhanced two-photon brightness, which would facilitate multiphoton microscopy.AimWe describe the development and applications of T-GECO1—a high-performance blue-shifted GECI based on the Clavularia sp.-derived mTFP1.ApproachWe use protein engineering and extensive directed evolution to develop T-GECO1. We characterize the purified protein and assess its performance in vitro using one-photon excitation in cultured rat hippocampal neurons, in vivo using one-photon excitation fiber photometry in mice, and ex vivo using two-photon Ca2+ imaging in hippocampal slices.ResultsThe Ca2+-bound state of T-GECO1 has an excitation peak maximum of 468 nm, an emission peak maximum of 500 nm, an extinction coefficient of 49,300 M−1 cm−1, a quantum yield of 0.83, and two-photon brightness approximately double that of EGFP. The Ca2+-dependent fluorescence increase is 15-fold, and the apparent Kd for Ca2+ is 82 nM. With two-photon excitation conditions at 850 nm, T-GECO1 consistently enabled the detection of action potentials with higher signal-to-noise (SNR) than a late generation GCaMP variant.ConclusionsT-GECO1 is a high-performance blue-shifted GECI that, under two-photon excitation conditions, provides advantages relative to late generation GCaMP variants.

Proceedings Article | 30 May 2022 Presentation

Presentation

A flexible two-photon endoscope for fast functional imaging and cell-precise optogenetic photo-stimulation of neurons in freely moving animals

Nicolò Accanto, François Blot, Valeria Zampini, Florence Bui, Antonio Lorca Camara, Christophe Tourain, Noam Badt, Ori Katz, Valentina Emiliani

Proceedings Volume PC12144, PC1214404 (2022) https://doi.org/10.1117/12.2624381

KEYWORDS: Neurons, Functional imaging, Optogenetics, Endoscopes, Photostimulation, Brain, Visualization, Reverse engineering, Neuroscience, Neuroimaging

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Understanding the causal relations between neuronal activity and behavior is one of the grand challenges of modern neuroscience. From a theoretical point of view, the requirements for reverse engineering the brain architecture are clear: we need to (1) measure neuronal activity from several individual cells, from which we can make hypothesis on their function; (2) manipulate (activate or inhibit) the same cells to test the accuracy of the hypothesis; (3) doing all this in animals during natural behavior. Two-photon (2P) micro-endoscopy could be the technological answer to these urgent needs and is today a thriving research field. However, 2P micro-endoscopy has so far focused on imaging neuronal activity, rather than manipulating it at will, which limits the ability to directly test possible causal links with behavior. To overcome this limitation, we have developed a new two-photon fiber bundle-based micro-endoscope (2P-FENDO) for the simultaneous functional imaging and optogenetic photostimulation of neurons in freely moving mice. By using computer generated holography, 2P-FENDO is capable of 2P optogenetic photostimulation of several neurons at once with cellular resolution. By optimising excitation and collection efficiencies, 2P-FENDO performs 2P functional imaging at one of the highest speeds so far demonstrated through an endoscope. Key novelty behind these results is the discovery that the fiber bundle, composed of ~15000 individual fiber cores, acts as a temporal multiplexing device, separating the laser pulses from each core in time of the right amount to avoid out of focus 2P fluorescence. This property results in a good axial resolution (< 15 µm) independently of the laser spot size. Proof-of-principle experiments were performed in head restrained and freely moving mice co-expressing jGcaMP7s and the opsin ChRmine in the visual or barrel cortex. On a field of view of 250 µm in diameter, we demonstrated functional imaging at a frame rate of up to 100 Hz and precise photostimulation of single and multiple cells (up to ~ 15, limited by the laser power, which could readily be increased with a more powerful photostimulation laser). With the capability to simultaneously image and control neuronal activity at single-cell resolution in freely moving animals, 2P-FENDO will enable to precisely define the functions of neurons in the brain and their interactions during naturalistic behaviours.

SPIE Journal Paper | 27 April 2022 Open Access

Open Access

Neurophotonic tools for microscopic measurements and manipulation: status report

Ahmed Abdelfattah, Srinivasa Rao Allu, Robert Campbell, Xiaojun Cheng, Tomáš Cižmár, Irene Costantini, Valentina Emiliani, Natalie Fomin-Thunemann, Ariel Gilad, Tomás Fernández Alfonso, Christopher G. Ferri, Andrew Harris, Elizabeth M. Hillman, Matthew Holt, Kivilcim Kiliç, Evan Miller, Rickson Mesquita, K.M. Naga Srinivas Nadella, U. Valentin Nägerl, Citlali Perez Campos, Francesca Puppo, Shy Shoham, R. Angus Silver, Vivek Srinivasan, Martin Thunemann, Lei Tian, Sergei Vinogradov, Flavia Vitale, Hana Uhlířová, Chris Xu, Mu-Han Yang, Yongxin Zhao, Sapna Ahuja, Taner Akkin, Joshua Brake, David Boas, Erin Buckley, Anderson Chen, Massimo De Vittorio, Anna Devor, Patrick Doran, Mirna El Khatib, Yeshaiahu Fainman, Xue Han, Ute Hochgeschwender, Na Ji, Evelyn Lake, Lei Li, Tianqi Li, Philipp Mächler, Yusuke Nasu, Axel Nimmerjahn, Petra Ondrácková, Francesco Pavone, Darcy Peterka, Filippo Pisano, Ferruccio Pisanello, Bernardo Sabatini, Sanaz Sadegh, Sava Sakadžic, Sanaya Shroff, Ruth Sims, Spencer Smith, Lin Tian, Thomas Troxler, Antoine Valera, Alipasha Vaziri, Lihong Wang, Changhuei Yang, Gary Yellen, Ofer Yizhar

NPh, Vol. 9, Issue S1, 013001, (April 2022) https://doi.org/10.1117/12.10.1117/1.NPh.9.S1.013001

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Proceedings Article | 4 March 2019 Presentation

Presentation

Multiplexed temporally focused light shaping for precise in-depth optogenetic stimulation (Conference Presentation)

Nicolò Accanto, Clement Molinier, Emiliano Ronzitti, I-Wen Chen, Dimitrii Tanese, Daniel Tomer, Eirini Papagiakoumou, Ori Katz, Valentina Emiliani

Proceedings Volume 10886, 108860R (2019) https://doi.org/10.1117/12.2507772

KEYWORDS: Optogenetics, Multiplexing, Brain, Scattering, Wavefronts, Microscopes, Neurons, Light scattering, Laser scattering, Two photon excitation microscopy

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SPIE Journal Paper | 12 May 2017 Open Access

Open Access

Imaging membrane potential changes from dendritic spines using computer-generated holography

Dimitrii Tanese, Ju-Yun Weng, Valeria Zampini, Vincent de-Sars, Marco Canepari, Balazs Rozsa, Valentina Emiliani, Dejan Zecevic

NPh, Vol. 4, Issue 03, 031211, (May 2017) https://doi.org/10.1117/12.10.1117/1.NPh.4.3.031211

KEYWORDS: Spine, Computer generated holography, Dendrites, Action potentials, Contamination, Light scattering

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Proceedings Article | 24 April 2017 Presentation

Presentation

Three-dimensional spatiotemporal focusing of holographic patterns (Conference Presentation)

Valentina Emiliani, Oscar Hernandez, Eirini Papagiakoumou, Dmitrii Tanese, Emiliano Ronzitti, Kevin Fidelin, Claire Wyart

Proceedings Volume 10076, 1007615 (2017) https://doi.org/10.1117/12.2255890

KEYWORDS: Computer generated holography, Biomedical optics, Tissue optics, Optogenetics, Luminescence, Holography, Channel projecting optics, Optical lithography, Spinal cord, Neurons

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Proceedings Article | 24 April 2017 Presentation

Presentation

Remote axial displacement of spatiotemporal focused patterns through neural systems (Conference Presentation)

Valentina Emiliani

Proceedings Volume 10073, 100731H (2017) https://doi.org/10.1117/12.2255823

KEYWORDS: Control systems, Light wave propagation, Computer generated holography, Optogenetics, Luminescence, Geometrical optics, Retina, Brain, Lithography, Functional imaging

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SPIE Journal Paper | 22 June 2016 Open Access

Open Access

Superresolving dendritic spine morphology with STED microscopy under holographic photostimulation

Marcel Lauterbach, Marc Guillon, Claire Desnos, Dany Khamsing, Zahra Jaffal, François Darchen, Valentina Emiliani

NPh, Vol. 3, Issue 04, 041806, (June 2016) https://doi.org/10.1117/12.10.1117/1.NPh.3.4.041806

KEYWORDS: Spine, Stimulated emission depletion microscopy, Microscopy, Holography, Computer generated holography, Spatial light modulators, Photostimulation, Mirrors, Neurons, Objectives

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SPIE Journal Paper | 7 January 2015 Open Access

Open Access

Computer-generated holography enhances voltage dye fluorescence discrimination in adjacent neuronal structures

Amanda Foust, Valeria Zampini, Dimitrii Tanese, Eirini Papagiakoumou, Valentina Emiliani

NPh, Vol. 2, Issue 02, 021007, (January 2015) https://doi.org/10.1117/12.10.1117/1.NPh.2.2.021007

KEYWORDS: Luminescence, Computer generated holography, Dendrites, Axons, Action potentials, Neurons, Signal to noise ratio, Neurophotonics, Cameras, Camera shutters

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Proceedings Article | 4 March 2009 Paper

Paper

Arbitrary two-dimensional multiphoton excitation patterns with temporally focused digital holograms

Dan Oron, Eirini Papagiakoumou, Vincent de-Sars, Valentina Emiliani

Proceedings Volume 7184, 71840S (2009) https://doi.org/10.1117/12.808489

KEYWORDS: Objectives, Digital holography, Speckle pattern, Holography, Holograms, Multiphoton microscopy, Optical lithography, Temporal resolution, Spatial light modulators, Diffraction gratings

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Proceedings Article | 20 April 2006 Paper

Paper

2D multiforce optical tweezers to investigate cell adhesion strengthening in living cells

Valentina Emiliani, Daniele Sanvitto, Christiane Durieux

Proceedings Volume 6195, 619508 (2006) https://doi.org/10.1117/12.661733

KEYWORDS: Optical tweezers, Luminescence, Microscopes, Digital image correlation, Proteins, Latex, CCD cameras, Optical filters, Cytoskeletons, Coating

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Proceedings Article | 20 April 2006 Paper

Paper

Wavefront engineering microscopy to study 3D mechanotransduction in living cells

Valentina Emiliani, Dan Cojoc, Enrico Ferrari, Valeria Garbin, Christiane Durieux, Enzo Di Fabrizio

Proceedings Volume 6195, 61950J (2006) https://doi.org/10.1117/12.662531

KEYWORDS: Spatial light modulators, Microscopes, Optical tweezers, Objectives, Luminescence, Wavefronts, 3D image processing, Molybdenum, 3D scanning, Diffractive optical elements

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Proceedings Article | 14 December 2005 Paper

Paper

Three-dimensional holographic optical tweezers implemented on spatial light modulator

Enrico Ferrari, Dan Cojoc, Valentina Emiliani, Valeria Garbin, Maïté Coppey-Moisan, Enzo Di Fabrizio

Proceedings Volume 5972, 597203 (2005) https://doi.org/10.1117/12.639172

KEYWORDS: Optical tweezers, Microscopes, Diffractive optical elements, Objectives, Spatial light modulators, Calibration, Holography, Video, Particles, Beam splitters

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Proceedings Article | 18 October 2004 Paper

Paper

Dynamic multiple beads manipulation on x-y-z directions

Dan Cojoc, Valentina Emiliani, Enrico Ferrari, Valeria Garbin, Enzo Di Fabrizio

Proceedings Volume 5514, (2004) https://doi.org/10.1117/12.557636

KEYWORDS: Particles, Diffractive optical elements, Spatial light modulators, Objectives, Molybdenum, Microscopes, Optical components, Optical spheres, Optical tweezers, Beam splitters

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Proceedings Article | 28 March 2000 Paper

Paper

Time-resolved near-field optical spectroscopy of single semiconductor quantum wires

Thomas Elsaesser, V. Emiliani, T. Guenther, F. Intonti, Christoph Lienau, Richard Noetzel, Klaus Ploog

Proceedings Volume 3940, (2000) https://doi.org/10.1117/12.381461

KEYWORDS: Quantum wells, Reflectivity, Luminescence, Near field, Gallium arsenide, Picosecond phenomena, Excitons, Femtosecond phenomena, Diffusion, Near field optics

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Proceedings Article | 19 November 1993 Paper

Paper

Near-surface quantum wells in GaAs: recovery of emission efficiency via surface passivation by hydrogen and stability effects

Andrea Frova, V. Emiliani, Mario Capizzi, B. Bonanni, Ying-Lan Chang, YongHang Zhang, James Merz

Proceedings Volume 1985, (1993) https://doi.org/10.1117/12.162809

KEYWORDS: Quantum wells, Quantum efficiency, Hydrogen, Gallium arsenide, Luminescence, Annealing

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Showing 5 of 16 publications

Conference Committee Involvement (2)

Advances in Microscopic Imaging

26 June 2019 | Munich, Germany

Neurophotonics

12 May 2013 | Munich, Germany

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