ABSTRACT
One long term effect on kittens of monocular or binocular deprivation is an asymmetry in the ease of eliciting optokinetic nystagmus (OKN) if the stimulus is presented monocularly. Asymmetrical OKN is found in very young kittens, and in mature cats with bilateral cortical lesions. The appearance of symmetrical OKN in development may indicate the development of cortical binocularity, or at least of a binocular pathway from cortex to pretectum. This chapter focuses on four experiments where the OKN will be examined relating to development, abnormal visual development, and its relationship to smooth pursuit movements. Smooth pursuit movements and the slow phase of OKN have similar velocity ranges and are both serving to stabilize a moving target on the retina, but it has widely been supposed that they represent the operation of two different mechanisms. This view gains support from the course of development.
