A sensory source for motor variation.

Journal Article (Journal Article)

Suppose that the variability in our movements is caused not by noise in the motor system itself, nor by fluctuations in our intentions or plans, but rather by errors in our sensory estimates of the external parameters that define the appropriate action. For tasks in which precision is at a premium, performance would be optimal if no noise were added in movement planning and execution: motor output would be as accurate as possible given the quality of sensory inputs. Here we use visually guided smooth-pursuit eye movements in primates as a testing ground for this notion of optimality. In response to repeated presentations of identical target motions, nearly 92% of the variance in eye trajectory can be accounted for as a consequence of errors in sensory estimates of the speed, direction and timing of target motion, plus a small background noise that is observed both during eye movements and during fixations. The magnitudes of the inferred sensory errors agree with the observed thresholds for sensory discrimination by perceptual systems, suggesting that the very different neural processes of perception and action are limited by the same sources of noise.

Full Text

Duke Authors

Cited Authors

  • Osborne, LC; Lisberger, SG; Bialek, W

Published Date

  • September 15, 2005

Published In

Volume / Issue

  • 437 / 7057

Start / End Page

  • 412 - 416

PubMed ID

  • 16163357

Pubmed Central ID

  • PMC2551316

Electronic International Standard Serial Number (EISSN)

  • 1476-4687

Digital Object Identifier (DOI)

  • 10.1038/nature03961


  • eng

Conference Location

  • England