Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 14: Neuronal and Sensory Systems
BP 14.2: Vortrag
Mittwoch, 25. März 2009, 14:30–14:45, HÜL 186
Living optical elements in the vertebrate retina — Moritz Kreysing1, Kristian Franze1, Boris Joffe2, Thomas Cremer2, Leo Peichl3, Andreas Reichenbach4, and •Jochen Guck1 — 1Cavendish Laboratory, University of Cambridge, GB — 2Institute of Human Genetics, LMU Munich, Germany — 3MPI for Brain Research, Frankfurt, Germany — 4Institute for Brain Research, University of Leipzig, Germany
While cells are mostly transparent they are phase objects that differ in shape and refractive index. Any image that is projected through layers of cells will normally be distorted. Strangely, the retina of the vertebrate eye is inverted and light must pass through several tissue layers before reaching the light-sensitive photoreceptor cells (PRC). Here we report how nature has optimized this apparently unfavourable situation. We investigated the optical properties of retinal tissue, individual Müller glial cells and PRC nuclei. We found that Müller cells act as optical fibers and guide light, which would otherwise be scattered, from the retinal surface to the PRCs. Their parallel arrangement in the retina is reminiscent of fiber-optic plates used for low-distortion image transfer. There is also a specific adaptation of the rod PRC nuclei for improved light transmission through the outer nuclear layer (ONL) of nocturnal animals. These nuclei have an inverted chromatin structure that turns them into micro-lenses channeling the light through the ONL. These findings ascribe a new function to glial cells, demonstrate the first nuclear adaptation for an optical function, and shed new light on the inverted retina as an optical system.