The hippocampus is damaged early in Alzheimer’s, while the thalamus is generally unaffected until the late stages. Brain imaging of the hippocampus and the thalamus in 31 patients with Alzheimer's and 68 healthy controls has revealed increased levels of iron in the hippocampus of those with Alzheimer’s, but not in the thalamus. Moreover, this increased iron was associated with tissue damage in patients with Alzheimer's but not in the healthy older individuals.
The findings support the view that iron accumulation is a factor in the development of Alzheimer's disease. It’s theorized that the buildup of tau and amyloid-beta is a response to the destruction of myelin. Myelin, and the oligodendrocytes that produces it, have the highest levels of iron of any cells in the brain.
http://www.eurekalert.org/pub_releases/2013-08/uoc--uss082013.php
Raven, E.P. 2013. Increased Iron Levels and Decreased Tissue Integrity in Hippocampus of Alzheimer’s Disease Detected in vivo with Magnetic Resonance Imaging. Journal of Alzheimer’s Disease, 37 (1), 127-136
