Neuroanatomy of magnetoreception: The superior colliculus involved in magnetic orientation in a mammal

The neural substrate subserving magnetic orientation is largely unknown in vertebrates and unstudied in mammals, We combined a behavioral test for mag netic compass orientation in mole rats and immunocytochemical visualization of the transcription factor c-Fos as a marker of neuronal activity. We fou nd that the superior colliculus of the Zambian mote rat (Cryptomys anselli) contains neurons that are responsive to magnetic stimuli. These neurons ar e directionally selective and organized within a discrete sublayer. Our res ults constitute evidence for the involvement of a specific mammalian brain structure in magnetoreception.