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1er juin 2018: 1 événement

  • Séminaires Invités

    Vendredi 1er juin 2018 14:00-15:30 - Cathie VENTALON - Institut de Biologie de l’ENS (IBENS), Paris

    Functional Fluorescence Imaging and Photoactivation in Freely-Behaving Mice

    Résumé : A longstanding goal in Neuroscience is to unravel the neural basis of perception, memory formation and behaviors. To address this goal, it can be useful to manipulate and record neuronal activity with cellular precision while the animal (here, a rodent) is performing specific behavioral tasks. Such experiments can be performed with optical methods, using photostimulation of optogenetic actuators and fluorescence imaging of calcium reporters. To apply optical methods to freely-behaving mice, two approaches have been followed : a microscope can be fully miniaturized and placed on the rodent head, or an image guide can be used as a relay between a regular-size custom-made microscope and the animal, which allows partly overcoming miniaturization constraints.
    Using this second strategy, we have recently developed two fiberscopes. The first system allows for photoactivation with near-cellular resolution in freely-behaving mice [1]. This is achieved by shaping the illumination beam for photoactivation using phase modulation with a liquid-crystal display. The second system allows for fast fluorescence imaging with optical sectioning, using multipoint- and line-scanning confocal imaging [2]. For both imaging modalities, the illumination beam is shaped by intensity modulation with a digital micro-mirror device, providing high adaptability to the sample and imaging conditions. Using this device, we demonstrated fast (>100 Hz) fluorescence imaging of blood flow and neuronal activity in the brain of freely-behaving mice, with reduced out-of-focus background compared with widefield imaging.
    [1] Szabo et al, Neuron 84, 1157–1169 (2014)
    [2] Dussaux et al, in preparation.

    contact : Delphine Débarre

    Lieu : LIPhy, conference room - 140 Avenue de la Physique 38402 Saint Martin d’Hères

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