Fred Gage, of the Salk Institute in La Jolla, California, and Mark Tuszynski, of the University of California, San Diego, have been tinkering not with controversial embryonic nerve cells, but with unassuming skin cells.

ECONOMIST: Something new in mind

Professor Tuszynski said that although it was still relatively early days, if the findings were confirmed it would be the first treatment that doctors had to actually prevent cell death in people with neurological diseases.

BBC: NEWS | Health | Alzheimer's gene therapy hailed

These are easy to grow in culture, so Dr Gage and Dr Tuszynski remove some from their experimental animals, add a few new genes to encourage them to make neuronal growth factors, and then let them multiply.

ECONOMIST: Something new in mind