Sprague effect
The Sprague effect is the phenomenon of the amelioration of homonymous hemianopia, caused by damage to visual cortex, by means of destruction of the contralesional superior colliculus. The effect is named for its discoverer, James Sprague, who observed this phenomenon in 1966 using the feline model. Several explanations have been proposed for this phenomenon, including mutual inhibition between the two brain hemispheres. For similar reasons of inhibiting an inhibitory structure, the lesioning of the substantia nigra, for instance by means of ibotenic acid, can also produce the same hemianopic amelioration.
