title: Changing and shielded magnetic fields suppress c-Fos expression in the navigation circuit: input from the magnetosensory system contributes to the internal representation of space in a subterranean rodent.
abstract: The neural substrate subserving magnetoreception and magnetic orientation in mammals is largely unknown. Previous experiments have demonstrated that the processing of magnetic sensory information takes place in the superior colliculus. Here, the effects of magnetic field conditions on neuronal activity in the rodent navigation circuit were assessed by quantifying c-Fos expression. Ansell's mole-rats (Fukomys anselli), a mammalian model to study the mechanisms of magnetic compass orientation, were subjected to natural, periodically changing, and shielded magnetic fields while exploring an unfamiliar circular arena. In the undisturbed local geomagnetic field, the exploration of the novel environment and/or nesting behaviour induced c-Fos expression throughout the head direction system and the entorhinal-hippocampal spatial representation system. This induction was significantly suppressed by exposure to periodically changing and/or shielded magnetic fields; discrete decreases in c-Fos were seen in the dorsal tegmental nucleus, the anterodorsal and the laterodorsal thalamic nuclei, the postsubiculum, the retrosplenial and entorhinal cortices, and the hippocampus. Moreover, in inactive animals, magnetic field intensity manipulation suppressed c-Fos expression in the CA1 and CA3 fields of the hippocampus and the dorsal subiculum, but induced expression in the polymorph layer of the dentate gyrus. These findings suggest that key constituents of the rodent navigation circuit contain populations of neurons responsive to magnetic stimuli. Thus, magnetic information may be integrated with multimodal sensory and motor information into a common spatial representation of allocentric space within this circuit.
authors.affiliation: Department of Zoology, Faculty of Science Charles University in Prague, Vinicna 7, CZ-12844 Praha 2, Czech Republic.
authors.forename: Tomás
authors.initials: T
authors.lastname: Burger
authors.forename: Marcela
authors.initials: M
authors.lastname: Lucová
authors.forename: Regina E
authors.initials: RE
authors.lastname: Moritz
authors.forename: Helmut H A
authors.initials: HH
authors.lastname: Oelschläger
authors.forename: Rastislav
authors.initials: R
authors.lastname: Druga
authors.forename: Hynek
authors.initials: H
authors.lastname: Burda
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wiltschko
authors.forename: Roswitha
authors.initials: R
authors.lastname: Wiltschko
authors.forename: Pavel
authors.initials: P
authors.lastname: Nemec
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D018891:Dentate Gyrus / Q000378:metabolism; D005260:Female; D006624:Hippocampus / Q000378:metabolism; D008280:Magnetics; D008297:Male; D019577:Mole Rats / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology*; D009949:Orientation; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D012677:Sensation / Q000235:genetics / Q000502:physiology; D013003:Somatosensory Cortex / Q000378:metabolism; D013028:Space Perception / Q000502:physiology*; D013477:Superior Colliculi / Q000378:metabolism
chemical_list: D016760:Proto-Oncogene Proteins c-fos