We propose to evaluate the usefulness of the ferret as an animal model of certain kinds of mental deficiency. The experiments will also suggest whether the ferret would provide a valuable test system for the screening of other potential central nervous system teratogens. We have already shown that methylazoxymethanol acetate can produce micrencephaly, lissencephaly, hydranencephaly, or cerebellar hypoplasia, depending on the gestation day on which it is given. We now propose to determine whether the severity of these malformations is dose dependent, by administration of different dosage schedules at the appropriate times. Several tests of cognitive and perceptual-motor function will be given to determine whether each of the brain malformations results in a different pattern of functional deficit. Serial sections of brains of each type will be prepared for both neuroanatomic and neuropathologic review. Similarities and differences among rodent, ferret, and human malformations will be emphasized. The micrencephalic ferret brain will be compared to the normal ferret brain on major biochemical parameters and the differences found related to those previously reported for micrencephalic and normal rat brains.