Synaptophysin (blue) in combination with donor and host markers. Donor processes (SC121; red) extend into host retina (rat-specific α-synuclein [IPL, amacrine cells]; green) and show synaptic connectivity by synaptophysin (blue) labeling. White arrows indicate examples of red/green/blue structures touching each other. Retina organoid transplant (six months post surgery) to retinal degenerate nude rat with responses in the brain. Modified after Figure 8c of McLelland et al. 2018, Investigative Ophthalmology & Visual Science.