The Unsteady Eye: An Information-Processing Stage, Not a Bug

Trends Neurosci. 2015 Apr;38(4):195-206. doi: 10.1016/j.tins.2015.01.005. Epub 2015 Feb 16.


How is space represented in the visual system? At first glance, the answer to this fundamental question appears straightforward: spatial information is directly encoded in the locations of neurons within maps. This concept has long dominated visual neuroscience, leading to mainstream theories of how neurons encode information. However, an accumulation of evidence indicates that this purely spatial view is incomplete and that, even for static images, the representation is fundamentally spatiotemporal. The evidence for this new understanding centers on recent experimental findings concerning the functional role of fixational eye movements, the tiny movements humans and other species continually perform, even when attending to a single point. We review some of these findings and discuss their functional implications.

Keywords: eye movements; microsaccades; neural encoding; ocular drift; retina; vision.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Eye Movements / physiology*
  • Fixation, Ocular / physiology
  • Humans
  • Motion Perception / physiology*
  • Ocular Physiological Phenomena*
  • Visual Pathways / physiology
  • Visual Perception / physiology*