A report in Nature Neuroscience has once again sparked interest in the use of foetal brain tissue to cure Parkinson's and other diseases. Dr Afsaneh Gaillard, of the University of Poitiers, in France, transplanted neurons from 14-day-old mice into mature mice with brain lesions. Two months later the grafts were well integrated into the host's brain tissue. If validated, according to a commentary by Mark Tuszynski in the journal, "the biology of this observation is stunning and the implications are important". "Attempts to repopulate the nervous system with fetal tissue or stem cells would merit very close examination".

Echoing Alan Greenspan's critique of stock market hype, however, Tuszynski warns against "unbridled and irrational exuberance". Other promising techniques have failed in the past, he points out.