Models of neurodegenerative disease - Alzheimer's anatomical and amyloid plaque imaging.

Alzheimer's disease (AD) is an important social and economic issue for our societies. The development of therapeutics against this severe dementia requires assessing the effects of new drugs in animal models thanks to dedicated biomarkers. According to the amyloid cascade hypothesis, β-amyloid deposits are at the origin of most of the lesions associated with AD. These extracellular deposits are therefore one of the main targets in therapeutical strategies. Aβ peptides can be revealed histologically with specific dyes or antibodies, or by magnetic resonance microscopy (μMRI) that uses their association with iron as a source of signal. The microscopic size of the lesions necessitates the development of specific imaging protocols. Most protocols use T (2)-weighted sequences that reveal the aggregates as hypointense spots. This chapter describes histological methods that reveal amyloid plaques with specific stains and MR-imaging protocols for in vivo and ex vivo MR imaging of AD mice.