Study offers evidence that toxic forms of Alzheimer's protein spread in the brain

Tau tangles are one half of the twin hallmark pathologies of Alzheimer's disease—the half that is most closely tied to the death of neurons. A study in the February 1 PLoS One offers evidence that the toxic forms of tau that cause these tangles spread throughout the brain by moving from one neuron to the next in a pattern that tracks anatomical synaptic connections of the earliest-hit nerve cells in the brain. This spread, the scientists found, recreates the typical disease progression usually observed in Alzheimer's, starting in a part of the brain called the entorhinal cortex.

This work made the front page of yesterday's New York Times. The Times article suggests that "Alzheimer's disease seems to spread like an infection from brain cell to brain cell...." Such an analogy may be misleading to the public, experts caution, implying falsely that Alzheimer's itself is contagious and can be passed between people.

In an Alzforum article posted today, reporter Tom Fagan takes apart this important scientific finding. Fagan puts it into the broader context of an emerging research trend, explains what it really means, and gets input from top experts in the field about why Alzheimer's cannot be caught like a cold.