Electrical Signals-Perception

Electroreception

Receiving electrical signals can give an animal any of three valuable inputs:

electrolocation information
receipt of communicatory information from other animals
location of other animals, particularly potential prey, which unintentionally produce electrical fields

Electroreception is common in fish and amphibia, but absent (or at least poorly understood) in terrestrial vertebrates and invertebrates. Animals cause local distortions of electrical fields and produce electrical currents whenever a nerve cell depolarizes (sends a signal) or a muscle contracts. Usually there are enough ions in the surrounding water to make the medium a good electrical conductor, and electrical currents and fields are excellent sources of information. Additionally, the interaction of water currents and the earth's magnetic field produces electrical fields which can be used in navigation.

Electroreceptors of fish include ampullary receptors, which are canals opening from the surface of the fish into cavities lined with nerve cells, and tuberous receptors, found on weakly electric fish (mormyriforms and gymnotoforms). The tuberous receptors have a similar structure to the ampullary receptors, but are designed to reduce the loss of the incoming signal.

Hagedorn, M. and Heiligenberg, W. 1985. Court and spark: Electric signals in the courtship and mating of gynotid fish. Anim. Behav. 33:254-265.

Hagedorn, M. and Zelick, R. 1989. Relative dominance among males is expressed in the electric organ discharge characteristics of a weakly electric fish. Anim. Behav. 38:520-525.

Heiligenberg W. 1990. Electrosensory systems in fish Synapse 6: (2) 196 206