Magnetoreception - Homing in on vertebrates

It has taken many years for acceptance of the principle that animals can navigate using a magnetic sense. The main problem has been in identifying an appropriate receptor. The discovery of magnetite, a permanently magnetic material, in various organisms provided an answer, but tracing the sensory system in vertebrates has proved difficult. New work with trout now takes knowledge a step further: the authors have mapped magnetoreceptive nerves back to the brain and to putative receptor cells. The next step is to establish whether or not the reflections in these cells, seen with confocal laser microscopy, are indeed caused by crystals of magnetite.