Magnetic sense

Molecular and cellular bases of the magnetic sense in animals

It has been known for a long time that animals are able to perform long distance migrations. For example, the arctic tern accomplishes a 35 000 km trans pole journey in order to experience two summers annually. Although researchers have demonstrated an involvement of visual and olfactory cues, these are not always available (i.e. overcast sky). Animals would therefore need to rely on a permanently present cue. Accumulation of evidence over the past 50 years does indeed suggest that animals utilise the geomagnetic field and possess an additional sense. However, the mechanisms by which a specialised cell can transduce magnetic information to the brain remain elusive. Since magnetic biological tissue are transparent to magnetic fields, detector cells could be placed anywhere within a given organism. Besides, magnetoreception is not a sense that humans possess (or at least are not aware of). The most recent advances in the field favour two possible mechanisms: a light-based mechanism and the presence of intracellular magnetic material. Based on the later hypothesis, we have developed unique techniques to detect and isolate magnetic cells using a combination of optical and cell sorting methods. Consequently, we have isolated magnetite-containing cells from fish olfactory epithelium. Standing on these results, the aim of our proposed project is therefore to establish a clear link between these cells and the animal magnetic sense. In order to achieve this goal, we will implement a combination of biophysical (magnetic cell sorting) and physiological (Calcium imaging on trout cells or transgenic zebrafish) techniques taking advantage of the valuable local neuroscience expertise.