Magnetosensation in zebrafish

• Published in: Current biology 2005-03, Vol.15 (5), p.R161-R162
• Main Authors: Shcherbakov, Denis, Winklhofer, Michael, Petersen, Nikolai, Steidle, Johannes, Hilbig, Reinhard, Blum, Martin
• Format: Article
• Language: English
• Subjects: Animals; Avoidance Learning - physiology; Conditioning (Psychology) - physiology; Electric Stimulation; Magnetics; Motor Activity - physiology; Reinforcement (Psychology); Sensation - physiology; Tilapia - physiology; Zebrafish - physiology
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2005.02.039

Many species, from bacteria to vertebrates, have been reported to use the geomagnetic field as a major cue for oriented short and long range migration [1–10], but the molecular nature of the underlying receptor has remained elusive. One of the main reasons may be that past attempts to train animals to respond to magnetic stimuli proved surprisingly difficult [11]. We present a novel approach to magnetic conditioning, using a fast, fully automated assay system relying on negative reinforcement. Weak electric impulses were applied to punish fish that failed to escape upon magnetic field alterations (avoidance behaviour). Using this assay we first demonstrate magnetosensation in Mozambique tilapia, a fish migrating regularly between freshwater and the sea. Next we wondered whether non-migratory fish have a magnetic sense, such as zebrafish, the genetic fish model organism. Zebrafish were trained in groups of 4 individuals, and statistically highly significant reactions to magnetic field changes were recorded. The demonstration of magnetosensation in zebrafish opens a possibility to genetically identify the magnetoreceptor and its downstream signalling cascade.