This image shows anterograde transneuronal labeling of postsynaptic granule cells (red) and presumed Golgi cells (red + green), but not Purkinje cells (green), after injection of a viral tracer into the pontine nucleus. All neurons are labeled with a fluorescent Nissl stain (blue), and inhibitory neurons are labeled via transgenic expression of GFP in GAD67+ neurons (green). For more information, see the article by Zingg et al. (pages 3250–3267).