title: Neural Correlates of Decision Thresholds in the Human Subthalamic Nucleus.
abstract: If humans are faced with difficult choices when making decisions, the ability to slow down responses becomes critical in order to avoid suboptimal choices. Current models of decision making assume that the subthalamic nucleus (STN) mediates this function by elevating decision thresholds, thereby requiring more evidence to be accumulated before responding [1-9]. However, direct electrophysiological evidence for the exact role of STN during adjustment of decision thresholds is lacking. Here, we show that trial-by-trial variations in STN low-frequency oscillatory activity predict adjustments of decision thresholds before subjects make a response. The relationship between STN activity and decision thresholds critically depends on the subjects' level of cautiousness. While increased oscillatory activity of the STN predicts elevated decision thresholds during high levels of cautiousness, it predicts decreased decision thresholds during low levels of cautiousness. This context-dependent relationship may be mediated by increased influence of the medial prefrontal cortex (mPFC)-STN pathway on decision thresholds during high cautiousness. Subjects who exhibit a stronger increase in phase alignment of low-frequency oscillatory activity in mPFC and STN before making a response have higher decision thresholds and commit fewer erroneous responses. Together, our results demonstrate that STN low-frequency oscillatory activity and corresponding mPFC-STN coupling are involved in determining how much evidence subjects accumulate before making a decision. This finding might explain why deep-brain stimulation of the STN can impair subjects' ability to slow down responses and can induce impulsive suboptimal decisions.
authors.affiliation: Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Mansfield Road, Oxford OX1 3TH, UK; Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK.
authors.forename: Damian M
authors.initials: DM
authors.lastname: Herz
authors.affiliation: Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK; Surgical Neurology Branch, National Institutes of Health, 10 Center Drive, 3D 20, Bethesda, MD 20814, USA.
authors.forename: Baltazar A
authors.initials: BA
authors.lastname: Zavala
authors.affiliation: Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Mansfield Road, Oxford OX1 3TH, UK; Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK.
authors.forename: Rafal
authors.initials: R
authors.lastname: Bogacz
authors.affiliation: Medical Research Council Brain Network Dynamics Unit at the University of Oxford, Mansfield Road, Oxford OX1 3TH, UK; Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK. Electronic address: peter.brown@ndcn.ox.ac.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Brown
mesh_terms: D003657:Decision Making; D046690:Deep Brain Stimulation; D004569:Electroencephalography; D006801:Humans; D007175:Impulsive Behavior; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D017397:Prefrontal Cortex / Q000502:physiology; D020531:Subthalamic Nucleus / Q000502:physiology*