Ling Wei, Shang Ping Yu, and colleagues at Emory University injected neural stem cells into the brains of mice after a stroke and activated the cells through nasal administration of a protein. The stem cells activated by this new, noninvasive technique called optochemogenetics grew healthier and formed more connections compared to the stem cells that did not receive stimulation. Additionally, the mice that received both stem cells and stimulation displayed the most recovery, with some behaviors returning to pre-stroke levels.

The combination of stem cell injection and stimulation increased the likelihood of a successful stroke recovery in mice. Instead of just injecting stem cells in the damaged area of the brain, following up with stimulation creates an ideal environment for the cells to develop and form connections with surrounding neurons.