Dynamic variability in vergence eye movements: a model based study

Variability is an intrinsic feature of physiological motor behavior. A minimal model that accurately simulates the initial component of vergence eye movements is used to quantify the variability of these responses. It was found that the adjustment of only four parameters could account for all of the variability seen within the movements of one subject and most of the variability could be attributed to just three parameters. Moreover, the variation of these three parameters showed significant inter-parameter correlation. A multiple regression analysis was used to isolate the functional relationships between these parameters. The implications of this analysis with regard to the neural mechanisms used to construct the preprogrammed initial component are discussed.