1 Unit of Functional Neurosurgery, Box 146, Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, University College London, 33 Queen Square, London WC1N 3BG, UK; Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK. Electronic address: l.zrinzo@ucl.ac.uk.
2 Unit of Functional Neurosurgery, Box 146, Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, University College London, 33 Queen Square, London WC1N 3BG, UK; Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK.
3 Unit of Functional Neurosurgery, Box 146, Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, University College London, 33 Queen Square, London WC1N 3BG, UK; Department of Neurosurgery, Umeå University, Umeå, Sweden.