This dissertation is based on the work carried out between September 2007 and August 2010 at the Center for Sensory-Motor Interaction, Aalborg University, Denmark. Experiments were performed at the Surgical Research Unit, Department of Colorectal Surgery, Aarhus University Hospital, Aarhus, Denmark. This work was made possible by financial support from The Danish National

Advanced Technology Foundation, Copenhagen, Denmark. A number of people should be acknowledged for contributing to the completion of this work.

Primarily I thank the patients who participated in the experiments, and without whom nothing of this would have been possible. I would like to thank my main supervisor Nico Rijkhoff for providing me thorough supervision and guiding my scientific education. I also want to thank my co-supervisor Søren Laurberg, Department of Surgery P, Aarhus University Hospital for a relentless enthusiasm, support and constructive criticism. Special thanks go to my other co-supervisor, Klaus Krogh, Department of Hepatology and Gastroenterology, Aarhus University Hospital for providing outstanding guidance, a superb ability to put things in perspective, and for always being available when things were challenging. Big thanks to colleagues and friends at the Surgical Research Unit, Department of Surgery P for excellent backing, and for creating a helpful and friendly environment. I also wish to give my warmest thanks to the staff at the Anal Physiology Laboratory, Aarhus University Hospital for always being positive and for assisting with the experiments in the most qualified manner. A special thanks to my parents, Ulla and Peter Henrik, and to my brother Kasper. Finally, I wish to thank my dear girlfriend Sofie for love and support, and for encouraging me when that was needed.