Visual asymmetries in Japanese quail (Coturnix japonica) retain a lifelong potential for plasticity.

Adult Japanese quail display left-eye/right-hemisphere dominance in visually guided sexual tracking. In 2 experiments, the authors set out to answer if this functional cerebral asymmetry is modifiable by posthatch monocular deprivation. In Experiment 1, the left or the right eye of 2-day old quail were closed for 70 days. Quail were run in a left- or a right-turning runway to obtain access to a conspecific of the opposite sex. The performance of both left and right eye systems was equal. In Experiment 2, the deprived eyes of the quail were opened and the previously open eyes were closed. They were tested with the same runways. Overall, running speed was very low, but the quail showed a left-eye/right-hemisphere superiority. Altogether, these experiments evince 3 insights into cerebral asymmetries in quail. First, posthatch asymmetries of visual input can alter lateralized behavior to an important extent. Second, cerebral asymmetries could involve an interhemispheric inhibition that can be modified by epigenetic factors. Third, even long-term visual deprivation does not abolish a previously established cerebral asymmetry.