Anatomic Studies on the Superior Colliculus

¹ Departments of Biological Structure and Neurological Surgery, University of Washington School of Medicine, Seattle, Wash. 98195

The superior colliculus is organized into a superficial zone which is directly connected with other parts of the visual system and a deep zone which is not directly connected with other visual centers. Within the superficial zone, there is a convergence of retinal and visual cortical afferents. The size, distribution, and synoptic patterns formed varies between animals. Removal of an eye in neonatal rats, at a time when there are few synapses formed in the colliculus, causes a great increase in the area of distribution of the uncrossed pathway of the remaining eye. At least some of the increased pathway arises from areas of retina which normally would have projected only contralaterally. Removal of an eye at later developmental stages results in no such abnormal projection, although there is evidence that synoptic sites formerly occupied by optic terminals became taken over by other neurons.

Key Words: superior colliculus • superficial layers • corticotectal pathway • retinotectal pathway • plasticity of connections

This article has been cited by other articles:

				T. Cunningham Early eye removal produces excessive bilateral branching in the rat: application of cobalt filling method Science, November 19, 1976; 194(4267): 857 - 859. [Abstract] [PDF]

				R. Lund and S. Hauschka Transplanted neural tissue develops connections with host rat brain Science, August 13, 1976; 193(4253): 582 - 584. [Abstract] [PDF]