Karl Friston is a professor of Neuroscience at University College London. His main contribution to theoretical neurobiology is a variational free energy principle. He is a world renowned theoretical neuroscientist and authority on brain imaging. Karl is a Fellow of the Academy of Medical Sciences, Fellow of the Royal Society of Biology and President of the international Organization of Human Brain Mapping. He received the Weldon Memorial prize and Medal in 2013 for contributions to mathematical biology. Karl holds Honorary Doctorates from the University of Zurich and Radboud University.