Invariant errors reveal limitations in motor correction rather than constraints on error sensitivity

Hyosub E Kim; J Ryan Morehead; Darius E Parvin; Reza Moazzezi; Richard B Ivry

doi:10.1038/s42003-018-0021-y

Invariant errors reveal limitations in motor correction rather than constraints on error sensitivity

Commun Biol. 2018 Mar 22:1:19. doi: 10.1038/s42003-018-0021-y. eCollection 2018.

Authors

Hyosub E Kim^{1

2}, J Ryan Morehead³, Darius E Parvin^{4

5}, Reza Moazzezi⁶, Richard B Ivry^{4

5}

Affiliations

¹ Department of Psychology, University of California, Berkeley, Berkeley, CA, 94720, USA. hyosubkim@berkeley.edu.
² Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA. hyosubkim@berkeley.edu.
³ John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.
⁴ Department of Psychology, University of California, Berkeley, Berkeley, CA, 94720, USA.
⁵ Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA.
⁶ Independent Investigator, Berkeley, CA, 94720, USA.

Abstract

Implicit sensorimotor adaptation is traditionally described as a process of error reduction, whereby a fraction of the error is corrected for with each movement. Here, in our study of healthy human participants, we characterize two constraints on this learning process: the size of adaptive corrections is only related to error size when errors are smaller than 6°, and learning functions converge to a similar level of asymptotic learning over a wide range of error sizes. These findings are problematic for current models of sensorimotor adaptation, and point to a new theoretical perspective in which learning is constrained by the size of the error correction, rather than sensitivity to error.

Grants and funding

R01 NS092079/NS/NINDS NIH HHS/United States