We add evidence from functional imaging supporting the concept of activation of coronally oriented zones corresponding to parallel fibers. Braitenberg et al.'s suggestion that there is an operating mode of the cerebellum relies on the idea introduced by Eccles and refined by the concept of tidal waves which Heck found in vitro. Recent evidence from functional imaging has shown zones of activation in accordance with this model and hence provides support for Braitenberg et al.'s hypothesis from the intact and healthy human cerebellum. In a second section, we discuss vulnerability of the structures described by Braitenberg et al. with respect to slow and fast movements in the context of clinical symptoms in cerebellar disease.