The mammalian superior colliculus (SC) is an important site of sensorimotor integration and both sensory and motor components lie in a compact vertical stack spanning no more than 2 mm.1 One of the most interesting findings related to the circuitry underlying these sensorimotor transformations is its periodicity. That is, numerous studies of many different afferent and efferent systems, in a wide variety of mammals, have demonstrated an inconceivable assortment of functionally diverse collicular afferents that exhibit discontinuous distributions, especially within the intermediate and deep layers of the SC. This brief review begins with the first widely cited description of SC patches (interestingly in the superficial layers) and concludes with a discussion of novel data published in the early 2000s. In the end, possible future studies are suggested.