Tonic vestibular control of eye position in postnatal developing rabbits.

With head and body fixed, 22 rabbits aged between 1st and 54th postnatal day were rotated step by step in 47 experiments over 360 degrees around their transverse and their longitudinal body axis, and in some cases around the horizontally placed dorsoventral body axis, too. The position of one eye, marked by burning a cornea stamp, was photographed after each rotation step. The observed eye positions in different tilt positions are always a consequence of combined horizontal, vertical and rolling eye movements, though compensatory counterrolling and compensatory vertical deviations of the eye predominated. During postnatal development in the rabbit, typical eye movement patterns as a course of eye positions during step by step 360 degrees rotation were formed until the second month of life. By reason of the polarization directions of their sensory cells, utricular maculae are obviously able to generate an innervation pattern for the tonic eye muscle contractions causing the observed eye movements.