Stimulation of the subthalamic nucleus and impulsivity: Release your horses

Authors

  • Benedicte Ballanger PhD,

    1. Division of Brain, Imaging and Behaviour–Systems Neuroscience, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    2. PET Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
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  • Thilo van Eimeren MD,

    1. Division of Brain, Imaging and Behaviour–Systems Neuroscience, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    2. PET Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
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  • Elena Moro MD, PhD,

    1. Movement Disorders Center, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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  • Andres M. Lozano MD, PhD,

    1. Division of Brain, Imaging and Behaviour–Systems Neuroscience, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    2. Department of Neurosurgery, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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  • Clement Hamani MD,

    1. Division of Brain, Imaging and Behaviour–Systems Neuroscience, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    2. Department of Neurosurgery, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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  • Philippe Boulinguez PhD,

    1. Center for Cognitive Neuroscience, Claude Bernard University, Lyon, France
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  • Giovanna Pellecchia PhD,

    1. PET Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
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  • Sylvain Houle MD, PhD,

    1. PET Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
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  • Yu Yan Poon RN,

    1. Movement Disorders Center, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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  • Anthony E. Lang MD,

    1. Division of Brain, Imaging and Behaviour–Systems Neuroscience, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    2. Movement Disorders Center, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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  • Antonio P. Strafella MD, PhD

    Corresponding author
    1. Division of Brain, Imaging and Behaviour–Systems Neuroscience, Toronto Western Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
    2. PET Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada
    3. Movement Disorders Center, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
    • Toronto Western Hospital & Institute, UHN, CAMH-PET Imaging Centre, University of Toronto, Toronto, ON, Canada
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  • Potential conflict of interest: Nothing to report.

Abstract

Objective

In Parkinson disease (PD) patients, deep brain stimulation (DBS) of the subthalamic nucleus (STN) may contribute to certain impulsive behavior during high-conflict decisions. A neurocomputational model of the basal ganglia has recently been proposed that suggests this behavioral aspect may be related to the role played by the STN in relaying a “hold your horses” signal intended to allow more time to settle on the best option. The aim of the present study was 2-fold: 1) to extend these observations by providing evidence that the STN may influence and prevent the execution of any response even during low-conflict decisions; and 2) to identify the neural correlates of this effect.

Methods

We measured regional cerebral blood flow during a Go/NoGo and a control (Go) task to study the motor improvement and response inhibition deficits associated with STN-DBS in patients with PD.

Results

Although it improved Unified Parkinson Disease Rating Scale motor ratings and induced a global decrease in reaction time during task performance, STN-DBS impaired response inhibition, as revealed by an increase in commission errors in NoGo trials. These behavioral effects were accompanied by changes in synaptic activity consisting of a reduced activation in the cortical networks responsible for reactive and proactive response inhibition.

Interpretation

The present results suggest that although it improves motor functions in PD patients, modulation of STN hyperactivity with DBS may tend at the same time to favor the appearance of impulsive behavior by acting on the gating mechanism involved in response initiation. Ann Neurol 2009;66:817–824

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