Visuomotor restriction of one eye in kittens reared with alternate monocular deprivation

It is known that kittens reared in ways that restrict movement while visual stimulation is received exhibit deficits in visually guided behavior. Presumably, the behavioral dysfunction is due to a lack of sensorimotor coordination during visual exposure. The current investigation was undertaken to study this effect both physiologically and behaviorally. Two groups of kittens were normally reared until they were nearly 4 weeks old. They were then placed in a darkroom and exposed daily for 1--2 hours while one eye was occluded. On alternate days, alternate eyes were covered. One group was restrained in a body cast while a given eye was exposed, but the kittens were free to move about while the other eye received visual experience. A second control group was alternately occluded, but freely mobile during all exposures. An additional cat was also unrestrained during daily rearing periods and neither eye was ever occluded. Behavioral tests showed clear deficits when the "passive" eye of the restrained-unrestrained group was used. Deficiencies were found in visually guided paw placing, pursuit eye movements, and jumping behavior to a platform. Responses of single cells were studied in area 17 of the visual cortex. Ocular dominance distributions showed marked reductions in binocularity for alternated occluder cats. The eye that had received exposure while animals were active in the restrained-unrestrained group also tended to predominate but the difference was not statistically significant.