title: Learning feedback and feedforward control in a mirror-reversed visual environment.
abstract: When we learn a novel task, the motor system needs to acquire both feedforward and feedback control. Currently, little is known about how the learning of these two mechanisms relate to each other. In the present study, we tested whether feedforward and feedback control need to be learned separately, or whether they are learned as common mechanism when a new control policy is acquired. Participants were trained to reach to two lateral and one central target in an environment with mirror (left-right)-reversed visual feedback. One group was allowed to make online movement corrections, whereas the other group only received visual information after the end of the movement. Learning of feedforward control was assessed by measuring the accuracy of the initial movement direction to lateral targets. Feedback control was measured in the responses to sudden visual perturbations of the cursor when reaching to the central target. Although feedforward control improved in both groups, it was significantly better when online corrections were not allowed. In contrast, feedback control only adaptively changed in participants who received online feedback and remained unchanged in the group without online corrections. Our findings suggest that when a new control policy is acquired, feedforward and feedback control are learned separately, and that there may be a trade-off in learning between feedback and feedforward controllers.
authors.affiliation: Faculty of Science and Technology, Keio University, Kanagawa, Japan;
authors.forename: Shoko
authors.initials: S
authors.lastname: Kasuga
authors.affiliation: Institute of Cognitive Neuroscience, University College London, London, United Kingdom;
authors.forename: Sebastian
authors.initials: S
authors.lastname: Telgen
authors.affiliation: Faculty of Science and Technology, Keio University, Kanagawa, Japan; Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan; and.
authors.forename: Junichi
authors.initials: J
authors.lastname: Ushiba
authors.affiliation: Graduate School of Education, The University of Tokyo, Tokyo, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Nozaki
authors.affiliation: Institute of Cognitive Neuroscience, University College London, London, United Kingdom; j.diedrichsen@ucl.ac.uk.
authors.forename: Jörn
authors.initials: J
authors.lastname: Diedrichsen
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology; D001696:Biomechanical Phenomena; D030141:Feedback, Psychological; D056228:Feedback, Sensory; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology; D011601:Psychophysics; D014796:Visual Perception; D055815:Young Adult
keywords: arm-reaching; feedback control; feedforward control; online correction; visuomotor transformation