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 magnetic compass orientation in mole rats and immunocytochemical visualization of the transcription factor c-Fos as a marker of neuronal activity. We found that the superior colliculus of the Zambian mote rat (Cryptomys anselli) contains neurons that are responsive to magnetic stimuli. These neurons are directionally selective and organized within a discrete sublayer. Our results constitute evidence for the involvement of a specific mammalian brain structure in magnetoreception.