 This paper examines an important and timely issue: the anatomical and functional connectivity from retina to superior colliculus to two target areas of the colliculus, the pulvinar and the parabigeminal nucleus. The paper uses a powerful combination of viral tracing, anatomy and electrophysiology to show that there is some specificity in this circuitry. The breadth of approaches is impressive, and I am quite enthusiastic about the overall aim of the work. There are several points, however, where the data does not fully support the conclusions drawn. These are detailed below. 