Refined electrophysiological recording and processing of neural signals from the retina and ascending visual pathways

Abstract

The purpose of this thesis was the development of refined methods for recording and processing of neural signals of the retina and ascending visual pathways. The first chapter describes briefly the fundamentals of the human visual system and the basics of the functional testing of the retina and the visual pathways. The second and third chapters are dedicated to the processing of visual electrophysiological data using the newly developed software ERG Explorer, and present a proposal for an open and standardized data format, ElVisML, for future proof storage of visual electrophysiological data. The fourth chapter describes the development and application of two novel electrodes: First a contact lens electrode for the recording of electrical potentials of the ciliary muscle during accommodation, and second, the marble electrode, which is made of a super-absorbant polymer and allows for a preparation-free recording of visual evoked potentials. Results obtained in studies using the both electrodes are presented. The fifths and last chapter of the thesis presents the results from four studies within the field of visual electrophysiology. The first study examines the ophthalmological assessment of cannabis-induced perception disorder using electrophysiological methods. The second study presents a refined method for the objective assessment of the visual acuity using visual evoked potentials and introduces therefore, a refined stimulus paradigm and a novel method for the analysis of the sweep VEP. The third study presents the results of a newly developed stimulus design for full-field electrophysiology, which allows to assess previously non-recordable electroretinograms. The last study describes a relation of the spatial frequency of a visual stimulus to the amplitudes of visual evoked potentials in comparison to the BOLD response obtained using functional near-infrared spectroscopy and functional magnetic resonance imaging.