Model systems of photoreceptor degeneration: Anatomical and physiological characterization and establishment of stimulation paradigms

• Applicants: Dr. Sandra Johnen; Professor Dr. Frank Müller; Professor Dr. Joachim Weis
• Subject Area: Microsystems ; Ophthalmology ; Clinical Neurology; Neurosurgery and Neuroradiology
• Term: from 2011 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 143692725

The aim of this project is to establish a method, which improves electrical stimulation of retinal ganglion cells by using a combination of pharmacological modulation and electrical conditioning.The results of our first funding period indicate that in different animal models of retinitis pigmentosa the retina shows a spontaneous rhythmic activity. In comparison to normal retina, ganglion cells in degenerated retina are electrically less excitable. We assume that this decrease in electrical excitability correlates with the appearance of the spontaneous activity. We found that the spontaneous activity is prevented by blocking of electrical synapses. Preliminary results indicate that an intense retinal stimulation mediated by electrical conditioning pulses allow for an improved stimulation of ganglion cells over a longer period of time. We believe that these results are very important for the BiMEA project and form the starting point for our new project part C. We will try to exactly evaluate the fundamental mechanisms of the retinal degeneration in the model of retinitis pigmentosa and combine electrical conditioning pulses with pharmacological modulation. This should enhance the electrical excitability of the degenerated retina and thus improve the efficiency of retinal implants. Therefore, the experimental results of the new project part C are particularly important for the accomplishment of the new project part D.

• DFG Programme: Research Grants