Group Jan Kremers

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Retinal Physiology

Aims

The retina is the neural part of the brain, where light is absorbed, transformed into an electrical signal, that is also processed and compressed in an efficient manner, so that it can be passed on to the brain. In most mammals the most important pathway for conscious visual perception is the retino-geniculo-cortico pathway (from the retina to the lateral geniculate nucleus of the thalamus and further to the cortex). It is the aim of the lab to reach a better understanding of the visual information processing in the retina and the lateral geniculate nucleus and its importance for visual perception. This knowledge is used to detect and understand the changes that occur when a retinal disease is present. The ultimate goal is to integrate all information to develop new or better treatments for these diseases.

Methods

To reach these goals, several methods are available in the laboratory. Electroretinography (ERG), an electrophysiological recording technique, can be used to study the function of the retina. When the retina is stimulated, the cells within the retina generate small electrical currents and potential changes that can be measured non-invasively by an electrode that is placed on the cornea. The relationship between light stimulus and the response tells something about the function of the retina and the functional deficits when a retinal disorder is present. We record ERGs in animals (normal animals, animal models for retinal diseases and genetically modified animals) and human subjects (healthy subjects and patients with a retinal disorder). The ERGs are recorded using a multitude of visual stimuli that can vary in their luminance, colour, temporal and spatial content.
To be able to correlate the physiology with visual perception, similar stimuli are used in psychophysical experiments. These experiments are performed with human subjects, who have to detect the stimulus or the difference between two stimuli. The results of these experiments are compared with those of the physiological experiments to allow conclusions about the importance of the physiological processes for vision. To understand the physiology and to relate the physiology with visual perception computational methods are used (development of mathematical models and computer programs that are used to simulate and predict the physiological processes).
Some imaging techniques are also available. A setup for multifocal ERG, where a spatial distribution map of ERG responses over the retina is obtained, is available. Simultaneously an image of the retina can be acquired, so that structure and function can be correlated. A correlation with structural and morphological parameters is also obtained by performing ERG recordings on animals that are intensively studied by other members of the Division of Animal Physiology.

Although not available in the laboratory, collaborations with other researchers can extent this palette of methods and may be established in the future. These techniques include single cell recordings, anatomy, and genetics.

 

Financial support

  • German Research Council
  • European Community
  • Bundesministerium für Bildung und Forschung (BMBF)
  • German Academic Exchange Council
  • Hertie Foundation
  • Novartis Institutes for BioMedical Research

 

External Collaborations

  • Prof. Dr. Michael Scholz, Anatomy II, University Hospital Erlangen, Germany

  • Prof. Dora Ventura, Dr. Mirella Barboni and Dr. Balázs Nagy Center of Neuroscience and Behavior / Dept. of Experimental Psychology, University of Sao Paulo, Brazil

  • Prof. Andrew Zele and Dr. Beatrix Feigl, Queensland University of Technology, Brisbane, Australien

  • Prof. Barry B. Lee Dept. of Optometry, SUNY, New York, USA

  • Prof. Luiz C. L. Silveira and Prof. Givago de Souza Dept. Fysiologia, Universidade federal do Pará, Belém, Brazil

  • Prof. Neil Parry and Dr. Ian Murray, Dept. of Ophthalmology and Dept. of Optometry and Neuroscience, University of Manchester, UK

  • Prof. Declan McKeefry, Bradford School of Optometry and Vision Science, Bradford University, UK

  • Dr. Günther Zeck, Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, Reutlingen