Laser focus

Stem cell treatments show promise for disorders such as Parkinson’s disease, which is characterized by defective nerve cells in specific brain regions. Results of stem cell transplants have been mixed, however, forcing researchers to guess what the cells are doing in the brain

Until now.

Scientists led by Jin Hyung Lee, PhD, assistant professor of neurology, of neurosurgery and of bioengineering, have devised a method of monitoring neural stem cells transplanted into rats’ brains.

Along with the cells, which contained a gene coding for a protein that induces electrical activity in response to blue laser light, the researchers implanted an optical fiber that could be connected to a light source. They then stimulated the cells with pulses of blue light.

Using fMRI and electrophysiology, the researchers were able to see that the cells matured into neurons and integrated into targeted circuits.

The cells also fired when stimulated by the light, triggering electrical activity in downstream nerve circuits.

“I’m hopeful that this monitoring approach could work for all kinds of stem-cell-based therapies,” says Lee, the senior author of the study, which was published in July 2015 in NeuroImage.