Where does an order to correct motor errors come from?
Brain mechanism behind trial-by-trial adaptation in reaching movements
A group of researchers led by Professor KITAZAWA Shigeru (Dynamic Brain Network Laboratory, Graduate School of Frontier Biosciences, Osaka University) and Researcher INOUE Masato (Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology) clarified that information about direction and size of errors in reaching movements appeared in the motor cortex.
Highlights
- The premotor and primary motor cortices encoded visual error in reaching.
- Stimulation to the motor cortices induced trial-by-trial increases in reach errors.
- The error increased opposite to the preferred direction of errors at each location.
- The after-effect of stimulation subsided gradually as in ordinary adaptation.
Summary
Reaching movements are subject to adaptation in response to errors induced by prisms or external perturbations. Motor cortical circuits have been hypothesized to provide execution errors that drive adaptation, but human imaging studies to date have reported that execution errors are encoded in parietal association areas. Thus, little evidence has been uncovered that supports the motor hypothesis. Here, we show that both primary motor and premotor cortices encode information on end-point errors in reaching. We further show that post-movement microstimulation to these regions caused trial-by-trial increases in errors, which subsided exponentially when the stimulation was terminated. The results indicate for the first time that motor cortical circuits provide error signals that drive trial-by-trial adaptation in reaching movements.
eTOC Blurb
Adaptation in reaching is a central issue in motor neuroscience. However, even the cortical origin of errors that drive adaptation has remained elusive. Here, Inoue et al. show that error signals encoded by motor cortical neurons drive adaptation in reaching.
To learn more about this research, please view the full research report entitled “ Error signals in motor cortices drive adaptation in reaching ” at this page of the Neuron website.
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