This work was done at the Neural Networks Research Centre of the Laboratory of Computer and Information Science in Helsinki University of Technology during the year 2004. I am grateful to my supervisor Academy Professor Erkki Oja and instructor Docent Ricardo Vigário for giving me the possibility to work in the Neuroinformatics group and allowing me to research this interesting topic for my thesis. I am also grateful to the whole group and the staff of the laboratory for the discussions which gave me many ideas for this thesis and future research. I would also like to thank Academy Professor Riitta Hari from the Advanced Magnetic Imaging Centre (AMI-Centre) and the Brain Research Unit of the Low Temperature Laboratory for discussions and invaluable physical and medical insight. Finally, I wish to thank my family and friends for encouraging and supporting me in my studies.
Otaniemi, March 3, 2005