title: Lateralized readiness potentials reveal properties of a neural mechanism for implementing a decision threshold.
abstract: Many perceptual decision making models posit that participants accumulate noisy evidence over time to improve the accuracy of their decisions, and that in free response tasks, participants respond when the accumulated evidence reaches a decision threshold. Research on the neural correlates of these models' components focuses primarily on evidence accumulation. Far less attention has been paid to the neural correlates of decision thresholds, reflecting the final commitment to a decision. Inspired by a model of bistable neural activity that implements a decision threshold, we reinterpret human lateralized readiness potentials (LRPs) as reflecting the crossing of a decision threshold. Interestingly, this threshold crossing preserves signatures of a drift-diffusion process of evidence accumulation that feeds in to the threshold mechanism. We show that, as our model predicts, LRP amplitudes and growth rates recorded while participants performed a motion discrimination task correlate with individual differences in behaviorally-estimated prior beliefs, decision thresholds and evidence accumulation rates. As such LRPs provide a useful measure to test dynamical models of both evidence accumulation and decision commitment processes non-invasively.
authors.affiliation: Department of Artificial Intelligence, University of Groningen, Groningen, The Netherlands.
authors.forename: Marieke K
authors.initials: MK
authors.lastname: van Vugt
authors.affiliation: Department of Neuroscience, Oberlin College, Oberlin, Ohio, United States of America.
authors.forename: Patrick
authors.initials: P
authors.lastname: Simen
authors.affiliation: Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America.
authors.forename: Leigh
authors.initials: L
authors.lastname: Nystrom
authors.affiliation: Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America; Department of Mechanical & Aerospace Engineering, Princeton University, Princeton, New Jersey, United States of America.
authors.forename: Philip
authors.initials: P
authors.lastname: Holmes
authors.affiliation: Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Cohen
mesh_terms: D000328:Adult; D001519:Behavior; D003265:Contingent Negative Variation; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009038:Motion; D009415:Nerve Net; D010465:Perception; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D059629:Signal-To-Noise Ratio; D055815:Young Adult