WORDS OF THANKS I want to thank… … my supervisor, Wim Van den Noortgate, who has guided me during these four years. Our meetings were the highlight of my week. He is an excellent mentor who gave me the freedom and the encouragement to realize my ideas. He gave me his unfailing help and support whenever I needed it. I am deeply grateful for the chance to work with him. … my co-supervisor, Piet Desmet, for his strategic vision and wise comments. … the members of my doctoral jury, Tom Beckers, Jan Elen, Dylan Molenaar, and Matthieu Brinkhuis, for agreeing to read my thesis and attend the defense. … my colleagues and friends,