Effects of early-onset artificial strabismus on pursuit eye movements and on neuronal responses in area MT of macaque monkeys.

Published

Journal Article

In humans, esotropia of early onset is associated with a profound asymmetry in smooth pursuit eye movements. When viewing is monocular, targets are tracked well only when they are moving nasally with respect to the viewing eye. To determine whether this pursuit abnormality reflects an anomaly in cortical visual motion processing, we recorded eye movements and cortical neural responses in nonamblyopic monkeys made strabismic by surgery at the age of 10-60 d. Eye movement recordings revealed the same asymmetry in the monkeys' pursuit eye movements as in humans with early-onset esotropia. With monocular viewing, pursuit was much stronger for nasalward motion than for temporalward motion, especially for targets presented in the nasal visual field. However, for targets presented during ongoing pursuit, temporalward and nasalward image motion was equally effective in modulating eye movement. Single-unit recordings made from the same monkeys, under anesthesia, revealed that MT neurons were rarely driven binocularly, but otherwise had normal response properties. Most were directionally selective, and their direction preferences were uniformly distributed. Our neurophysiological and oculomotor measurements both suggest that the pursuit defect in these monkeys is not due to altered cortical visual motion processing. Rather, the asymmetry in pursuit may be a consequence of imbalances in the two eyes' inputs to the "downstream" areas responsible for the initiation of pursuit.

Full Text

Duke Authors

Cited Authors

  • Kiorpes, L; Walton, PJ; O'Keefe, LP; Movshon, JA; Lisberger, SG

Published Date

  • October 15, 1996

Published In

Volume / Issue

  • 16 / 20

Start / End Page

  • 6537 - 6553

PubMed ID

  • 8815931

Pubmed Central ID

  • 8815931

International Standard Serial Number (ISSN)

  • 0270-6474

Language

  • eng

Conference Location

  • United States