title: Changes in the stimulus-preceding negativity and lateralized readiness potential during reinforcement learning.
abstract: According to reinforcement learning theory, dopamine-dependent anticipatory processes play a critical role in learning from action outcomes such as feedback or reward. To better understand outcome anticipation, we examined variation in slow cortical potentials and assessed their changes over the course of motor-skill acquisition. Healthy young adults learned a series of precisely timed, key press sequences. Feedback was delivered at a delay of either 2.5 or 8 s, to encourage use of either the striatally mediated, habit learning system or the hippocampus-dependent, episodic memory system, respectively. During the 2.5-s delay, the stimulus-preceding negativity (SPN) was shown to decline in amplitude across trials, confirming previous results from a perceptual categorization task (Morís, Luque, & Rodríguez-Fornells, 2013). This falsifies the hypothesis that SPN reflects specific outcome predictions, on the assumption that the ability to make such predictions should improve as a task is mastered. An SPN was also evident during the 8-s delay, but it increased in amplitude across trials. At the conclusion of the 8-s but not the 2.5-s prefeedback interval, a reversed-polarity lateralized readiness potential (LRP) was noted. It was suggested that this might indicate maintenance of an action representation for comparison with the feedback display. If so, this would constitute the first direct psychophysiological evidence for a popular hypothetical construct in quantitative models of reinforcement learning, the so-called eligibility trace.
authors.affiliation: Department of Psychological Sciences, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: Xi
authors.initials: X
authors.lastname: Ren
authors.affiliation: Department of Psychology, University of La Coruña, La Coruña, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Valle-Inclán
authors.affiliation: Institute of Biology, Taras Shevchenko National University of Kiev, Kiev, Ukraine.
authors.forename: Sergii
authors.initials: S
authors.lastname: Tukaiev
authors.affiliation: Department of Psychological Sciences, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Hackley
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D003265:Contingent Negative Variation; D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009048:Motor Skills; D012054:Reinforcement, Psychology; D012201:Reward; D055815:Young Adult
keywords: efference copy; feedback; lateralized readiness potential; reinforcement learning; reward; stimulus-preceding negativity