Plasticity in the oculomotor system.

The oculomotor system, responsible for the control of eye movement, is capable of a number of kinds of plasticity. The demonstration of such plasticity has been aided by several factors, including the present delineation of the system's major subsystems and their purposes; the relatively simple relationships between the system and the mechanical apparatus on which it acts, the eyeball and its muscles; and the development of techniques for studying central nervous system (CNS) activity in awake, behaving animals. Plasticity has been demonstrated by using noninvasive techniques to disturb the normal relationship between vision and eye movements, thereby creating a need for adjustment by the oculomotor system. Current studies are concerned with the location and identity of the responsible modifiable synapses. The cerebellum and the olivocerebellar pathways are definitely involved in several forms of oculomotor plasticity. However, it remains to be determined whether the responsible changes reside within these structures or are located elsewhere in the CNS.