A hypothetical explanation of congenital nystagmus

Lance M. Optican, David Samuel Zee

Research output: Contribution to journalArticle

Abstract

Congenital nystagmus (CN) is a conjugate, rhythmic, eye movement disorder characterized by a wide variety of waveforms ranging from jerk to pendular types. No detailed mechanisms have been proposed to explain the generation of the CN wave-form This paper proposes a hypothetical mechanism for CN, and shows with computer simulations that a model based on this hypothesis can account for a variety of disparate waveforms. The basis of this model is a gaze-holding network, or neural integrator, that has both position and velocity feedback loops. The signals carried in these loops could arise from either afference or efference. In normal subjects, the position feedback would be positive and the velocity feedback would be negative. Both would help to increase the time constant of an imperfect neural integrator in the brain stem. We propose that in patients with CN the sign of the velocity pathway is reversed, making the neural integrator unstable. This instability could manifest as many different CN waveforms, depending on the direction and velocity of post-saccadic ocular drift and actions of nonlinearities within the position and velocity feedback loops. Thus a single underlying abnormality may be responsible for a variety of CN waveforms.

Original languageEnglish (US)
Pages (from-to)119-134
Number of pages16
JournalBiological Cybernetics
Volume50
Issue number2
DOIs
StatePublished - Apr 1984

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Congenital Nystagmus
Eye movements
Feedback
Ocular Motility Disorders
Computer Simulation
Brain Stem
Brain
Computer simulation

ASJC Scopus subject areas

  • Biophysics

Cite this

A hypothetical explanation of congenital nystagmus. / Optican, Lance M.; Zee, David Samuel.

In: Biological Cybernetics, Vol. 50, No. 2, 04.1984, p. 119-134.

Research output: Contribution to journalArticle

Optican, Lance M. ; Zee, David Samuel. / A hypothetical explanation of congenital nystagmus. In: Biological Cybernetics. 1984 ; Vol. 50, No. 2. pp. 119-134.
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