The brain must consider the arm's inertia to predict the arm's movements elicited by commands impressed upon the muscles. Here, we present evidence suggesting that the integration of sensory information leading to the representation of the arm's inertia does not take place continuously in time but only at discrete transient events, in which kinetic energy is exchanged between the arm and the environment. We used a visuomotor delay to induce cross-modal variations in state feedback and uncovered that the difference between visual and proprioceptive velocity estimations at isolated collision events was compensated by a change in the representation of arm inertia. The compensation maintained an invariant estimate across modalities of the expected energy exchange with the environment. This invariance captures different types of dysmetria observed across individuals following prolonged exposure to a fixed intermodal temporal perturbation and provides a new interpretation for cerebellar ataxia.
Data files for this manuscript are available through Dryad doi:10.5061/dryad.93kc5cb
Data from: Energy exchanges at contact events guide sensorimotor integration across intermodal delaysAvailable at Dryad Digital Repository under a CC0 Public Domain Dedication.
- Ferdinando A Mussa-Ivaldi
The funders had no role in study design, data collection, and interpretation, or the decision to submit the work for publication.
Human subjects: The study protocol was approved by Northwestern University's Institutional Review Board (STU00026226) and all the participants signed an informed consent form.
- Richard Ivry, University of California, Berkeley, United States
© 2018, Farshchian et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.