Short-term adaptive control processes in vergence eye movement

John L. Semmlow, Weihong Yuan, Tara Alvarez

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

The "Dual Mode" theory for the control of disparity vergence eye movements states that two control components, a preprogrammed "transient" component, and a feedback control "sustained component, mediate the motor response. Although prior experimental work has isolated and studied the transient component, little is known of the contribution of the sustained component to vergence response. The timing between the two components and their relative magnitudes are of interest as they have implications on the control strategies used to coordinate the two components. Modeling studies can provide an estimate of component magnitudes, but cannot uniquely identify the component timing. The work presented in this paper applies Principal Component Analysis (PCA) to ensemble data both to confirm the presence of two major components and for data reduction. A novel, ensemble version of Independent Component Analysis (ICA), is then exploited to estimate the contribution of the two control components to the eye movement. Other recent experiments have shown that the vergence system is capable of rapidly modifying its dynamic characteristics (short-term adaptation) when exposed to specially designed "adapting" stimuli. Adapted responses were characterized by faster dynamics often featuring large overshoots. ICA analysis of adapted and normal responses show that the enhanced dynamics of adapted responses are due to an increase in transient component amplitude. In addition, the sustained component of adapted responses often showed double-step behavior in the later portion of the response. Finally, the extent of adaptation produced appeared to be related to the unadapted transient component amplitude.

Original languageEnglish (US)
Pages (from-to)343-375
Number of pages33
JournalCahiers de Psychologie Cognitive
Volume21
Issue number4-5
StatePublished - Oct 1 2002

All Science Journal Classification (ASJC) codes

  • Experimental and Cognitive Psychology
  • Psychology(all)

Keywords

  • Disparity vergence response
  • Eye movements
  • Independent component analysis
  • Vergence components

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