Physiology of Tuberous Electrosensory Systems

Abstract

Abstract Tuberous electrosensory systems are found in two orders of weakly electrogenic fishes, the Gymnotiformes of South America and the Mormyriformes of Africa. Tuberous electrosensory systems in both of these clades encode perturbations of the autogenous electric field produced by each fish. Here we review some of the organizational features and mechanisms used in tuberous electrosensory systems to represent information and extract salient features from these perturbations. At the periphery, electrosensory neurons use combinations of rate and/or timing codes to broadly encode information. This information is subjected to complex filtering at the first stage of processing in the central nervous system, a hindbrain structure known as the electrosensory lateral line lobe (ELL). Neurons in the ELL also receive massive descending feedback that dramatically alters their encoding properties. Neurons in the ELL in turn transmit electrosensory information to the midbrain where complex features, such as moving objects and certain social signals, are extracted.