This could be one of the most dramatic breakthroughs in the search for a cure for neurodegenerative disease in our lifetime.
Professor Giovanna Mallucci and her team in Britain have found a pathway to stop the death of brain tissue.
That opens a new route to stopping diseases like Alhzeimer's, Parkinson's, Huntington's and others.
Doctor Mallucci told BBC News they focued on the natural defence mechanisms built into brain cells and they developed a chemical that stops the cells from destroying themselves.
"We've given a drug-like compound to mice and prevented brain degeneration and that's a first," says Mallucci.
The problem is, the chemical is not safe for humans.
"This is not a drug and it is not a treatment, at the moment, but it gives us a target to design and work out better substances and drugs that don't have side-effects, as this one does, to be able to have a new target to be able to prevent brain cell death," she says.
In other words, drug companies now have a starting point.