In tests with lab mice, researchers think that they may have isolated the specific protein that causes the formation of unnatural "clumps" of protein inside of nerve cells, resulting in the neurofibrillary tangles thought to be one of the causes of Alzheimer's disease. The protein, named Tau by researchers, is normally a key protein found in all healthy nerve cells, but a rogue form of the protein misbehaves, and triggers the cells to form neurofibrillary tangles, an abnormal behavior.

Researchers, led by a group from the University Hospital, Basel, first extracted the Tau protein from mice who were previously encouraged via genetic manipulation to express the mutated human Tau protein. When these Tau proteins were were injected into the brains of healthy mice, the injected proteins began forming the protein tangles linked to Alzheimer's. Moreover, in a particularly important turn of events, not only did the previously normal healthy Tau proteins begin to clump and form neurofibrillary tangles, those tangles spread to other, healthy, nearby sections of the brain.

This is the first clearly laboratory-documented instance of the defective proteins spreading and damaging healthy tissue. Understanding how the neurofibrillary tangles spread is potentially helpful in terms of discovering how to stop them, and perhaps even prevent them from forming. This is of course assuming that genetically modified mice brains behave the way naturally mutated Tau proteins in human brains behave. At the very least, the way the neurofibrillary tangles spread to healthy tissues is similar to the damage caused by prions in diseases like Variant Creutzfeldt-Jakob disease.