Studies of mammalian spatial cognition have focused primarily on visual landmarks and self-generated cues (optic flow, vestibular cues, etc.) that operate over relatively short distances, and largely ignored the global reference provided by the earth's magnetic field that can be used to place local arrays of visual landmarks into register to form a map of familiar space. Evidence that the magnetic compass of birds and at least some rodents (i.e., mice and rats) may be mediated by magnetically sensitive photoreceptors in the retina has led to speculation that the magnetic field may be perceived as a complex, 3-dimensional pattern of light intensity or color superimposed on the animal's surroundings. This pattern could function as a simple spherical grid or coordinate system that helps to encode directional and spatial input from other sensory modalities. Behavioral studies have shown that mice have a well-developed magnetic compass, but there is no information for mice or any other mammal on how magnetic and non-magnetic cues interact. The proposed research will use a mouse water maze assay to investigate the relative salience of magnetic and visual landmark cues when both types of cues are present, and to determine whether mice that learn a directional response relative to the magnetic field will transfer the learned relationship to visual landmarks, and vice versa. Broader impacts of this research include: (1) understanding the role of a novel sensory input (magnetic cues) in a behavioral assay widely used in biomedical research (e.g., to study Alzheimer's disease and other forms of dementia), (2) providing undergraduate students from diverse backgrounds with interdisciplinary research training, and (3) collaborating with a nationally recognized expert on interdisciplinary training and assessment to develop materials to assess undergraduate research.
