Magnetoreception.
The vector of the geomagnetic field provides animals with directional information, while intensity and/or inclination provide them with positional information. For magnetoreception, two hypotheses are currently discussed: one proposing magnetite-based mechanisms, the other suggesting radical pair processes involving photopigments. Behavioral studies indicate that birds use both mechanisms: they responded to a short, strong magnetic pulse designed to change the magnetization of magnetite particles, while, at the same time, their orientation was found to be light-dependent and could be disrupted by high-frequency magnetic fields in the MHz range, which is diagnostic for radical pair processes. Details of these findings, together with electrophysiological and histological studies, suggest that, in birds, a radical pair mechanism located in the right eye provides directional information for a compass, while a magnetite-based mechanism located in the upper beak records magnetic intensity, thus providing positional information. The mechanisms of magnetoreception in other animals have not yet been analyzed in detail.
Wiltschko
Roswitha
R
Fachbereich Biowissenschaften der J.W. Goethe-Universität Frankfurt am Main, Germany.
Wiltschko
Wolfgang
W
D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D004594:Electrophysiology; D052203:Ferrosoferric Oxide; D008027:Light; D008280:Magnetics; D008954:Models, Biological
D052203:Ferrosoferric Oxide