Cortical lateralization of function in rats in a visual reaction time task.

Rats were trained to orient to a visual cue presented in either visual field. An asymmetry in reaction time showed that they used one eye to control responses to both visual fields. Cortical removal contralateral to this dominant eye produced a severe and permanent response deficit. Cortical removal ipsilateral to the dominant eye caused a mild and temporary change. Thus, in the rat, there is a functional lateralization that is similar to that seen in humans.