They read the chemical signalling of the tissue, which indicate areas of stress. And then they go and try to repair the situation,' said Cohen.

The next step is to develop a real-life therapy for those suffering from neuro-degenerative diseases. The ultimate goal is to repair neuronal cells and tissues.

Stem cell therapy is thought to be the most promising future therapy to combat diseases such as Huntington's, Alzheimer's and Parkinson's diseases, and researchers may also be able to develop a therapy for stroke victims.

If post-stroke cell degeneration can be stopped at an early stage, said Cohen, patients can live for many years with a good quality of life.

His findings were reported in the journal Stem Cells.