The impact of low frequency stimulation of the pedunculopontine nucleus region on reaction time in parkinsonism Running title: Impact of stimulation of PPN area on reaction time Wesley Thevathasan FRACP, 1,2 Peter A Silburn FRACP, 4,5 Helen Brooker BSc, 3 Terry J Coyne FRACS, 4 Sadaquate Khan FRCS, 6 Steven S Gill FRCS, 6 Tipu Z Aziz DMedSc, 2 Peter Brown FRCP 1,* 1 Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK 2 Nuffield Department of Surgery, University of Oxford, UK 3 Cognitive Drug Research Ltd, Goring-on-Thames, UK 4 St Andrews and Wesley Hospitals, Brisbane, Australia 5 Centre for Clinical Research, Royal Brisbane and Womens Hospital, University of Queensland, Australia 6 Institute of Neurosciences, Frenchay Hospital, Bristol BS16 1LE, United Kingdom * Correspondence: Prof. P. Brown Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London, WCIN 3BG. Tel/fax: +44 (0) 845 155 5000 Ext 18764 / +44 (0)20 7278 9836 Email p.brown@ion.ucl.ac.uk Word counts : Abstract = 268; Main text = 3487 Abbreviations: PPN = Pedunculopontine nucleus; DBS = Deep brain stimulation; UPDRS = Unified Parkinson’s Disease Rating Scale; IT27/30 = items 27-30 of Unified Parkinson’s Disease Rating Scale; PD = Parkinson’s disease; FOG/PI = Freezing of Gait and Postural Instability; RT = Reaction Time Keywords : Pedunculopontine; Deep brain stimulation; Parkinson’s disease; Reaction time The Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive licence (or non-exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd and its Licensees to permit this article (if accepted) to be published in Journal of Neurology, Neurosurgery & Psychiatry and any other BMJPGL products to exploit all subsidiary rights, as set out in our licence peer-00557411, version 1 - 19 Jan 2011 Author manuscript, published in "Journal of Neurology, Neurosurgery & Psychiatry 81, 10 (2010) 1099" DOI : 10.1136/jnnp.2009.189324