1 Section of Neurosurgery, Department of Medical Sciences, Uppsala University, 751 85, Uppsala, Sweden. teodor.svedung-wettervik@neuro.uu.se.
2 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK. teodor.svedung-wettervik@neuro.uu.se.
3 Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.