This study evaluated the two types of Persian cats, the traditional doll-face and the newer Peke-face, for a correlation between brachycephalic (short-faced) traits and
internal hydrocephaly, or abnormal accumulation of cerebrospinal fluid (the fluid that bathes the brain and spinal cord) in the brain.
Histological observations showed brain defects, dilation in the 3rd and 4th ventricles (internal hydrocephaly), absence of 3rd and 4th ventricles (internal microcephaly) and under developed lateral part of cerebellum.
Sections from dose group 12.5 ug/g B.W showed dilation of 3rd and 4th ventricles known as internal hydrocephaly (Fig, 2C, D).