title: Microsaccade direction reflects the economic value of potential saccade goals and predicts saccade choice.
abstract: Microsaccades are small-amplitude (typically <1°), ballistic eye movements that occur when attempting to fixate gaze. Initially thought to be generated randomly, it has recently been established that microsaccades are influenced by sensory stimuli, attentional processes, and certain cognitive states. Whether decision processes influence microsaccades, however, is unknown. Here, we adapted two classic economic tasks to examine whether microsaccades reflect evolving saccade decisions. Volitional saccade choices of monkey and human subjects provided a measure of the subjective value of targets. Importantly, analyses occurred during a period of complete darkness to minimize the known influence of sensory and attentional processes on microsaccades. As the time of saccadic choice approached, microsaccade direction became the following: 1) biased toward targets as a function of their subjective value and 2) predictive of upcoming, voluntary choice. Our results indicate that microsaccade direction is influenced by and is a reliable tell of evolving saccade decisions. Our results are consistent with dynamic decision processes within the midbrain superior colliculus; that is, microsaccade direction is influenced by the transition of activity toward caudal saccade regions associated with high saccade value and/or future saccade choice.
authors.affiliation: Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; and.
authors.forename: Gongchen
authors.initials: G
authors.lastname: Yu
authors.affiliation: Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; and.
authors.forename: Baijie
authors.initials: B
authors.lastname: Xu
authors.affiliation: Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; and.
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; and.
authors.forename: Beizhen
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; and.
authors.forename: Mingpo
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Biomedical and Molecular Sciences, Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada.
authors.forename: Janis Ying Ying
authors.initials: JY
authors.lastname: Kan
authors.affiliation: Department of Biomedical and Molecular Sciences, Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada.
authors.forename: David Martin
authors.initials: DM
authors.lastname: Milstein
authors.affiliation: Department of Biomedical and Molecular Sciences, Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada.
authors.forename: Dhushan
authors.initials: D
authors.lastname: Thevarajah
authors.affiliation: Institute of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; and mike.dorris@ion.ac.cn.
authors.forename: Michael Christopher
authors.initials: MC
authors.lastname: Dorris
mesh_terms: D000328:Adult; D000818:Animals; D002755:Choice Behavior; D005260:Female; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D012201:Reward; D012438:Saccades; D013477:Superior Colliculi / Q000502:physiology
keywords: Nash equilibrium; decision making; expected value; microsaccades; mixed strategy; reward