New research has shown that human “mini brains” can integrate with damaged rat brains to perform functions related to sight — a promising step toward a future where lab-grown brain tissue can reverse blindness in people. The caveats: While about 75% of the neurons in the rats’ own visual cortices responded to the light stimulation, only 20% of those in the grafted human mini brains did. ”Looking ahead: As is the case with all rat studies, there’s a chance humans would respond to this procedure in a completely different way, so much more research is needed before anyone could try using organoids to repair brain damage in people