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TL Alvarez, JL Semmlow, T Simms, W Yuan; Adaptive Changes In Disparity Vergence Eye Movements . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1494.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:Based upon the Dual-Mode Theory, vergence eye movements are composed of two components, a vergence initiating component and a vergence sustaining component. The vergence initiating component brings the eyes close to the target of interest and is depicted by an open-loop or pulse process; whereas the vergence sustaining component accounts for the accuracy of the vergence oculomotor system and is depicted by a feedback or step process. The ability to adapt a neuro-muscular system is imperative for species survival. This study will research if the vergence system can adapt and acquire a negative gain in the high-velocity portion of vergence eye movements. Methods:Vergence eye movements were recorded using an infrared limbus tracking system in response to one degree and four-degree step stimuli. There were two phases to the experiment, an adapting phase (where the ratio of one degree to four degree steps was 3:1 or 5:1) and a nonadapting phase (where the ratio of one degree to four degree steps was 1:1.) Results:A dynamic analysis using the main sequence (peak velocity as a function of response amplitude) was performed on four-degree responses to determine if the smaller stimuli were adapting the high-velocity component of the larger responses. Preliminary results depict a decrease in the peak velocity for adapted responses compared to non-adapted responses. This adaptation is believed to be modifying the pulse or fusing initiating component. Conclusion:Smaller degree responses can evoke a short-term adaptation on larger responses as depicted by a small decrease in the gain of the high-velocity response.
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