Reduced corpus callosum, fornix and hippocampus in PDAPP transgenic mouse model of Alzheimer's disease

Persons with Alzheimer's disease (AD) have progressive reductions in the re lative sizes of the corpus callosum and hippocampus. Homozygotic PDAPP tran sgenic mice over-expressing a mutant form of the human amyloid precursor pr otein have more pronounced reductions in these regions, which are apparent prior to the deposition of amyloid plaques and do not progress with advanci ng age. The length of the corpus callosum was reduced by two-thirds, the fo rnix commissure was negligible, and the hippocampal volume was reduced by o ne-third, suggesting a massive disconnection between the cerebral hemispher es and the hippocampi in PDAPP mice. These findings, which might account fo r the early, nonprogressive behavioral abnormalities observed in these anim als, have implications for the study of AD. NeuroReport 12:2375-2379 (C) 20 01 Lippincott Williams & Wilkins.