title: Human subthalamic nucleus-medial frontal cortex theta phase coherence is involved in conflict and error related cortical monitoring.
abstract: The medial prefrontal cortex (mPFC) is thought to control the shift from automatic to controlled action selection when conflict is present or when mistakes have been recently committed. Growing evidence suggests that this process involves frequency specific communication in the theta (4-8Hz) band between the mPFC and the subthalamic nucleus (STN), which is the main target of deep brain stimulation (DBS) for Parkinson's disease. Key in this hypothesis is the finding that DBS can lead to impulsivity by disrupting the correlation between higher mPFC oscillations and slower reaction times during conflict. In order to test whether theta band coherence between the mPFC and the STN underlies adjustments to conflict and to errors, we simultaneously recorded mPFC and STN electrophysiological activity while DBS patients performed an arrowed flanker task. These recordings revealed higher theta phase coherence between the two sites during the high conflict trials relative to the low conflict trials. These differences were observed soon after conflicting arrows were displayed, but before a response was executed. Furthermore, trials that occurred after an error was committed showed higher phase coherence relative to trials that followed a correct trial, suggesting that mPFC-STN connectivity may also play a role in error related adjustments in behavior. Interestingly, the phase coherence we observed occurred before increases in theta power, implying that the theta phase and power may influence behavior at separate times during cortical monitoring. Finally, we showed that pre-stimulus differences in STN theta power were related to the reaction time on a given trial, which may help adjust behavior based on the probability of observing conflict during a task.
authors.affiliation: Nuffield Department of Clinical Neurology, University of Oxford John Radcliffe Hospital, Oxford, OX3 9DU, UK; Surgical Neurology Branch, National Institutes of Health, 10 Center Drive, 3D20, Bethesda, MD 20814, USA. Electronic address: zarzavala@gmail.com.
authors.forename: Baltazar
authors.initials: B
authors.lastname: Zavala
authors.affiliation: Nuffield Department of Clinical Neurology, University of Oxford John Radcliffe Hospital, Oxford, OX3 9DU, UK; Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Mansfield Road, OX1 3TH, UK.
authors.forename: Huiling
authors.initials: H
authors.lastname: Tan
authors.affiliation: Department of Neurosurgery, King's College Hospital, King's College, London SE5 9RS, UK.
authors.forename: Keyoumars
authors.initials: K
authors.lastname: Ashkan
authors.affiliation: Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London WC1 3BG, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Foltynie
authors.affiliation: Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London WC1 3BG, UK.
authors.forename: Patricia
authors.initials: P
authors.lastname: Limousin
authors.affiliation: Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London WC1 3BG, UK.
authors.forename: Ludvic
authors.initials: L
authors.lastname: Zrinzo
authors.affiliation: Surgical Neurology Branch, National Institutes of Health, 10 Center Drive, 3D20, Bethesda, MD 20814, USA.
authors.forename: Kareem
authors.initials: K
authors.lastname: Zaghloul
authors.affiliation: Nuffield Department of Clinical Neurology, University of Oxford John Radcliffe Hospital, Oxford, OX3 9DU, UK; Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Mansfield Road, OX1 3TH, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Brown
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping; D003220:Conflict, Psychological; D003344:Cortical Synchronization / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000502:physiology*; D020531:Subthalamic Nucleus / Q000502:physiology*; D013826:Theta Rhythm / Q000502:physiology*
keywords: Coherence; Conflict; Errors; Subthalamic nucleus; Theta