The role of structural symmetry in linearizing ocular reflexes

This work presents a simulation study using an anatomically relevant model of the vestibulo-ocular reflex (VOR). The aim is to explore the functional properties of a bilateral structure in the premotor circuits of the oculomotor system. The major conclusions using sinusoidal inputs are: A bilateral structure in a sensory-motor system improves its linear range beyond expected central limits, if provided with symmetric interconnections. Given a bilateral (push-pull) sensory arrangement, non-linear sensor characteristics are actually advantageous. The greatest improvement in linear range of the reflex (here VOR) relies on intact sensors on both sides. In the case of a single sensor (unilateral head velocity input), or unmatched bilateral sensors, this study predicts a decrease in the linear range and the appearance of a variable bias. These implications are compatible with available data and can be tested in a clinical invironment.