Focal spongy changes in the central nervous system of sheep and cattle.

A focal form of vacuolation in the white matter of the thalamus of 13 sheep and 2 cattle is described. The individual vacuoles were similar in appearance to those reported in other forms of spongy degeneration, but they were differentiated by their consistent neuroanatomical localization in the thalamic radiation of all 15 animals. Thirteen of these were sheep used in toxicity experiments and 11 had shown signs of convulsive activity.