Accumulations of Fat in the Brains of Mice Affected with Scrapie

SUMMARY Accumulations of neutral fat were found, especially in the grey matter, in the brains of all of 18 mice affected with scrapie; their nature and distribution were fundamentally different from lesions previously reported. Certain areas of the brain were consistently affected, particularly the caudal region o f the hippocampus, the anterior group of thalamic nuclei, the substantia nigra and the molecular layer of the cerebellar cortex. The fatty lesions, in common with other changes in scrapie, showed pronounced bilateral symmetry. They were not apparently accompanied by any specific cellular or tissue response in the same foci and were not shown to be dependent on myelin degeneration. Fifteen control mice not affected with scrapie did not contain fat in the areas considered to be predilection sites in affected animals.