Tracking Alzheimer's-linked protein in live brains

Scientists for the first time have peered into people's brains to directly measure the ebb and flow of a substance notorious for its role in Alzheimer's disease. The delicate research was performed not with Alzheimer's patients but with people suffering severe brain injuries — because a brain injury increases the risk of developing dementia later in life. 

The goal is to learn why, so that doctors one day might be able to lower that risk.
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