Optimal reaching subject to computational and physical constraints reveals structure of the sensorimotor control system

Patrick Greene, Amy J. Bastian, Marc H. Schieber, Sridevi V. Sarma

Research output: Contribution to journalArticlepeer-review

Abstract

Optimal feedback control provides an abstract framework describing the architecture of the sensorimotor system without prescribing implementation details such as what coordinate system to use, how feedback is incorporated, or how to accommodate changing task complexity. We investigate how such details are determined by computational and physical constraints by creating a model of the upper limb sensorimotor system in which all connection weights between neurons, feedback, and muscles are unknown. By optimizing these parameters with respect to an objective function, we find that the model exhibits a preference for an intrinsic (joint angle) coordinate representation of inputs and feedback and learns to calculate a weighted feedforward and feedback error. We further show that complex reaches around obstacles can be achieved by augmenting our model with a path-planner based on via points. The path-planner revealed “avoidance” neurons that encode directions to reach around obstacles and “placement” neurons that make fine-tuned adjustments to via point placement. Our results demonstrate the surprising capability of computationally constrained systems and highlight interesting characteristics of the sensorimotor system.

Original languageEnglish (US)
Article numbere2319313121
JournalProceedings of the National Academy of Sciences of the United States of America
Volume121
Issue number14
DOIs
StatePublished - Apr 2 2024

Keywords

  • computational neuroscience
  • motor control
  • optimal feedback
  • sensorimotor system

ASJC Scopus subject areas

  • General

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