Effects of fixational saccades on response timing in macaque lateral geniculate nucleus

Vis Neurosci. 2010 Nov;27(5-6):171-81. doi: 10.1017/S0952523810000258. Epub 2010 Oct 8.

Abstract

Even during active fixation, small eye movements persist that might be expected to interfere with vision. Numerous brain mechanisms probably contribute to discounting this jitter. Changes in the timing of responses in the visual thalamus associated with fixational saccades are considered in this study. Activity of single neurons in alert monkey lateral geniculate nucleus (LGN) was recorded during fixation while pseudorandom visual noise stimuli were presented. The position of the stimulus on the display monitor was adjusted based on eye position measurements to control for changes in retinal locations due to eye movements. A method for extracting nonstationary first-order response mechanisms was applied, so that changes around the times of saccades could be observed. Saccade-related changes were seen in both amplitude and timing of geniculate responses. Amplitudes were greatly reduced around saccades. Timing was retarded slightly during a window of about 200 ms around saccades. That is, responses became more sustained. These effects were found in both parvocellular and magnocellular neurons. Timing changes in LGN might play a role in maintaining cortical responses to visual stimuli in the presence of eye movements, compensating for the spatial shifts caused by saccades via these shifts in timing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Action Potentials / physiology
  • Algorithms
  • Animals
  • Artifacts
  • Cell Size
  • Color
  • Data Interpretation, Statistical
  • Fixation, Ocular / physiology*
  • Geniculate Bodies / cytology
  • Geniculate Bodies / physiology*
  • Macaca mulatta
  • Neurons / physiology
  • Neurons / ultrastructure
  • Photic Stimulation
  • Saccades / physiology*
  • Space Perception / physiology
  • Visual Fields