X-ray holographic nano-tomography to reveal the structure of neural circuits and more
Vendredi 30 août 2019 11:00
- Duree : 1 heure
Lieu : Salle des séminaires de l’IBS - 71, avenue des Martyrs - Grenoble
Orateur : Alexandra PACUREANU (ERSF & University College London)
Bringing to light the neural circuits underlying sensory, motor, behavioral or cognitive functions is essential to advance our understanding of the nervous system and to discover therapeutic approaches for neurological diseases. This knowledge provides as well
a basis for developing artificial intelligence and the next generation computing chips. With current technology, we are not able to both resolve the nanometer sized, dense circuit elements and to cover the extensive tissue volumes they span. Electron microscopy is the only
technique offering sufficient spatial resolution, but imaging tissue volumes requires ultrathin sectioning and subsequent alignment and stitching of millions of images. This is highly challenging and entails months or years of data collection and prohibitive costs. Today, the largest brain imaged entirely corresponds to a fruit fly and it remains a unique data set. Hard X-ray microscopy could potentially enable imaging of large intact tissues at nanometer scale thanks to high penetration power and sub-nanometer wavelength. However, the spatial resolution and contrast achieved in practice so far were not sufficient to visualize the axons and dendrites in nervous tissue. I will present recent developments in cryogenic holographic nano-tomography with a highly focused and brilliant X-ray source. This technique makes possible imaging of dense neuronal morphologies in extensive tissue samples. More generally, X-ray holography enables nanoscale, rapid 3D imaging of both stained and label-free tissues and cells with exceptional contrast. In addition, I will discuss the possibility to extract knowledge from the large and complex generated data using machine learning, more specifically convolutional neural networks.
Contact : ibs.seminaires@ibs.fr
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