Alzheimer plaques precede neuron damage

linkurl:Alzheimer's;http://www.the-scientist.com/article/home/53215/ disease researchers have long tried to address a linkurl:key question:;http://www.the-scientist.com/article/display/15006/ Do amyloid plaques cause the disease, or do other disease mechanisms come first? A new linkurl:study;http://www.nature.com/nature/journal/v451/n7179/abs/nature06616.html published today (February 6) in Nature reports that plaques form immediately before neurite damage, suggesting that amyloids do play a direct role on the pathway to dementia. The researchers, led by Bradley Hyman at Massachusetts General Hospital, used an in vivo imaging technique in a mouse Alzheimer's model to observe how and where plaques form over time. They observed that plaques formed very quickly over 24 hours, followed by the recruitment of microglia, which did not clear plaques but prevented any further plaque formation. The group also observed changes in neurites following the formation of plaques; they saw neuritic deformation after two days of plaque formation, and after three to four days neurites began wasting away. "This is the first study to really...