Elsevier

Vision Research

Volume 37, Issue 9, May 1997, Pages 1197-1205
Vision Research

Convergence and Divergence Exhibit Different Response Characteristics to Symmetric Stimuli

https://doi.org/10.1016/S0042-6989(97)00271-XGet rights and content
Under an Elsevier user license
open archive

Abstract

The dynamic characteristics of horizontal convergence and divergence eye movement responses to symmetric stimuli were examined. Binocular eye movements were recorded in five, visually normal adult subjects using the infrared reflection technique for symmetric convergent and divergent blurfree, disparity-only, step stimuli of 2, 4, 8, 12, and 16 deg. The main sequence as well as other temporal parameters including latency, time-to-peak velocity, time constant, and total duration were analyzed. A number of fundamental differences in the response characteristics were found between convergence and divergence. First, the slope of the peak velocity vs amplitude curve was approximately twice as high for convergence than divergence. The results are consistent with neurophysiological findings in monkeys and most findings in humans. Second, the initial fast component for convergence exhibited a larger amplitude than for divergence. This may reflect differences in central neural gain for convergence and divergence. And, third, all temporally related components were shorter for convergence than divergence. These findings provide an overall framework for vergence control and suggest fundamental differences in neural processing delays and neural controller pathways for convergence and divergence. © 1997 Elsevier Science Ltd. All rights reserved.

Keywords

Convergence
Divergence – Main sequence – Motoneuronal control – Neurophysiology of eye movements

Cited by (0)