Writing a dissertation is associated with many Ups and Downs. It goes without saying that all this time is accompanied by the motivation and support of others. Therefore, I would like to thank the most important people shortly at this point.First of all I would like to thank Professor Rainer Marggraf for giving me the possibility to be part of his research chair, to achieve my Ph.D. and to introduce me to Dr. Jan Barkmann whom I would like to thank the most. He gave me the chance to work in my homeland in a good and meaningful project. His support, suggestions, guidance, talks and crucial thoughts were invaluable for me. I am grateful for his support to overcome barriers during my work at the University. Thank you, Jan.I would like to thank Professor Stephan von Cramon-Taubadel to be a member of my doctoral thesis committee. The very same thanks counts for Professor Emilia Nercissians with whom I had a lot of nice and productive time while drinking coffee and other beverages. My thanks count also to Dr. Johanna Schott who was my "Ph.D.-Mother" and always supported me in my thesis and above.Thank you to all my project colleagues: Gizo,