Figure 1: Whole-brain Ca2+-imaging of larval zebrafish in-vivo using light-field deconvolution microscopy at 20Hz volume rate.

Figure 1: Whole-brain Ca2+-imaging of larval zebrafish in-vivo using light-field deconvolution microscopy at 20Hz volume rate. a Maximum intensity projection of cross sections with individual cells represented by colored overlays (scale bar 100µm). b Extracted Ca2+ intensity signal (∆F/F0) of GCaMP5 fluorescence using spatial filters shown in a. Each row shows a time-series heat map. Arrow denotes the addition of an aversive odor.

+++ At EMBL from August 2016 +++

The Prevedel group develops new optical techniques for investigating dynamic cellular processes deep inside tissue in-vivo.

Light microscopy has revolutionized our understanding in many areas of biology, and over the years tremendous progress has been achieved by imaging cellular and subcellular processes in transparent, fixed, or thin sample preparations. Yet in order to obtain a complete understanding of biological processes, in-vivo studies inside thick, three-dimensional living tissues are often required. However, when light interacts with thick biological tissue, the process of light scattering leads to low-resolution, ‘blurry’ images and an effective loss of excitation power with increasing imaging depth. This has severely limited the biomedical usefulness of light microscopy to, e.g., cultured cells in vitro or superficial layers of tissue in vivo. New approaches and tools are thus required to noninvasively image biological function at depth inside living tissue with sufficient resolution, speed and contrast.

Previous and current research

In the past, we have developed novel optical techniques for high-speed imaging, with a particular focus on functional imaging in the neurosciences. Amongst others, we have put forward a two-photon microscopy technique based on light-sculpting that has enabled the first whole-brain calcium imaging in C. elegans. In other work, we have established light-field deconvolution microscopy, an elegant approach to perform volumetric imaging that achieves unprecedented acquisition speeds while requiring no mechanical scanning. Currently, we extend our imaging methods to the scattering tissue domain and combine our approach with longer-wavelength excitation and red-shifted indicators, which collectively allow for larger imaging depth. Together with our collaborators, we apply our methods to study neuronal activity in a range of model organisms such as C. elegans, zebrafish larvae and behaving mice.

Future projects and goals

The future focus of the group is to push the frontiers of deep tissue microscopy in terms of imaging depths and resolution by developing advanced and innovative optical imaging techniques. To do so we will draw from diverse fields such as multi-photon microscopy, active wave-front shaping, photo-acoustics as well as computational imaging. In particular, we aim to bridge the technological gap in spatial resolution and imaging depth that exists between optical microscopy and longer wavelength approaches such as photo-acoustics. We intend to combine these into multi-modal imaging systems that allow studying cellular processes and dynamics at depths inaccessible so far by conventional microscopy. Our multidisciplinary team comprises of physicists, engineers, computer scientists and biologists, and we engage in close collaboration with fellow groups at EMBL in the fields of cell and developmental biology as well as neuroscience.