title: In Parkinson's disease on a probabilistic Go/NoGo task deep brain stimulation of the subthalamic nucleus only interferes with withholding of the most prepotent responses.
abstract: The evidence on the impact of subthalamic nucleus deep brain stimulation (STN-DBS) on action restraint on Go/NoGO reaction time (RT) tasks in Parkinson's disease (PD) is inconsistent; with some studies reporting no effect and others finding that STN stimulation interferes with withholding of responses and results in more commission errors relative to STN-DBS off. We used a task in which the probability of Go stimuli varied from 100% (simple RT task) to 80, 50 and 20% (probabilistic Go/NoGo RT task), thus altering the prepotency of the response and the difficulty in withholding it on NoGo trials. Twenty PD patients with STN-DBS, ten unoperated PD patients and ten healthy controls participated in the study. All participants were tested twice; the order of on versus off stimulation for STN-DBS PD patients was counterbalanced. Both STN-DBS and unoperated PD patients were tested on medication. The results indicated that STN-DBS selectively decreased discriminability when the response was most prepotent (high--80%, as compared to low Go probability trials--50 and 20%). Movement times were faster with STN stimulation than with DBS off across different Go probability levels. There was neither an overall nor a selective effect of STN-DBS on RTs depending on the level of Go probability. Furthermore, compared to healthy controls, both STN-DBS and unoperated PD patients were more prone to making anticipatory errors; which was not influenced by STN stimulation. The results provide evidence for 'load-dependent' effects of STN stimulation on action restraint as a function of the prepotency of the Go response.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
authors.forename: Dejan
authors.initials: D
authors.lastname: Georgiev
authors.affiliation: Department of Clinical Neuroscience, Danube University, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Dirnberger
authors.affiliation: Behavioural Neurology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Centre Dr., MSC 1440, Bethesda, MD, 20892-1440, USA.
authors.forename: Leonora
authors.initials: L
authors.lastname: Wilkinson
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
authors.forename: Patricia
authors.initials: P
authors.lastname: Limousin
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK. m.jahanshahi@ucl.ac.uk.
authors.forename: Marjan
authors.initials: M
authors.lastname: Jahanshahi
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D010775:Photic Stimulation / Q000379:methods*; D011930:Reaction Time / Q000502:physiology*; D020531:Subthalamic Nucleus / Q000502:physiology*
keywords: Deep brain stimulation (DBS); Go/NoGo task; Load-dependent effects; Parkinson’s disease (PD); Prepotency; Subthalamic nucleus (STN)