Credit: Cell Press

A protein that accumulates in the brain with normal ageing as well as with Alzheimer's disease can be tracked using human brain imaging for the first time.

Scientists could previously map the insoluble form of the protein tau in human brain tissue only after death. To follow changes in tau levels and distribution over time, William Jagust at the University of California, Berkeley, and his colleagues used a previously developed molecule that labels tau for positron emission tomography (PET) imaging (pictured) in living people. Compared with young people, healthy older people had increased tau in the medial temporal lobe, an area involved in memory. Higher levels of the protein predicted a poorer performance on certain memory tasks. Older adults with suspected Alzheimer's disease had the highest levels of tau. Across all older participants, the spread of tau to other brain areas correlated with higher levels of amyloid-β protein, which is also associated with Alzheimer's disease.

The technique could be used to monitor brain health and test drug candidates, the authors suggest.

Neuron 89, 971–982 (2016)