1 From the Radiology Institute (Ž.S.) and Institute of Clinical Neurophysiology, Division of Neurology (G.O.), University Medical Centre Ljubljana, Zaloška 7, Ljubljana 1000, Slovenia; Institute of Anatomy, Faculty of Medicine (Ž.S., U.M.), and Institute of Anatomy, Faculty of Medicine (E.C.), University of Ljubljana, Ljubljana, Slovenia; and Condensed Matter Physics Department, Jožef Stefan Institute, Ljubljana, Slovenia (I.S.).