Vision in tree shrews (Tupia glis) after removal of striate cortex

Abstract

Three tree shrews (Tupaia glis) were trained to discriminate between horizontal and vertical stripes, and upright and inverted triangles. The striate cortex of both hemispheres was then ablated. All animals relearned the habits based on the discrimination of visual patterns. Histological study of the thalamus revealed a complete degeneration of the lateral geniculate bodies. On the basis of these findings and on the basis of the unlearned behavior of the operated animals in both familiar and unfamiliar circumstances it is concluded that pattern and object vision do not depend on the geniculostriate system in this particular species.