Most of all I should like to thank my parents for providing me the possibilities to endeavor into science. Next, of course, my gratitude goes to Prof. Dr. Martin Heisenberg for his constant encouragement during this study and for the enlightening discussions without which the progress of this work would have been at stake. Of inestimable value for my study was Reinhard Wolf without whom all the programs and other equipment would not have worked. Moreover, I profited much by his experience, his intensive feedback and constant flow of ideas. I also want to thank Matthias Porsch, Martin Barth, Reinhard Wolf, Jean-René Martin and Gerold Wustmann for volunteering for the test of spike detection efficiency. I'm also indebted to Chris Cutts from the University of Glasgow for checking the thesis for language errors. During all of my time working I have been inspired by interesting discussions during our weekly sessions in the behavior group and by the congenial atmosphere in the Department of Genetics and the Biocenter.