STRUCTURE AND FUNCTION OF THE VERTEBRATE MAGNETIC SENSE

Some vertebrates can navigate over long distances using the Earth's ma gnetic field, but the sensory system that they use to do so has remain ed a mystery. Here we describe the key components of a magnetic sense underpinning this navigational ability in a single species, the rainbo w trout (Oncorhynchus mykiss), We report behavioural and electrophysio logical responses to magnetic fields and identify an area in the nose of the trout where candidate magnetoreceptor cells are located. We hav e tracked the sensory pathway from these newly identified candidate ma gnetoreceptor cells to the brain and associated the system with a lear ned response to magnetic fields.