Biomaterial Database

Noise autocorrelation and jamming avoidance performance in pulse type electric fish. 2004

Alberto Capurro, and C P Malta

Instituto de Física, Universidade de São Paulo (USP), Rua do Matão, Travessa R187, Cidade Universitária, Butantã, 05508-900 São Paulo, Brazil. alberto@fma.if.usp.br

The amplitude and the autocorrelation level of the noise affecting the interval between successive electric organ discharges were estimated in isolated fish and in socially interacting fish of the species Gymnotus carapo. Both quantities increased in the fish with the slower discharging rate of the pair during the interaction, and we aim to assess whether they have some functional implication for the efficiency of the jamming avoidance response performed by the fish having the faster discharging rate of the pair. For this purpose, the noisy variability of the intervals around its mean value was simulated using autoregressive models estimated from experimental recordings of isolated and interacting fish. The simulation was implemented using two autoregressive models, each representing one fish of the pair. The jamming avoidance response was included by adding transient interval shortenings to the train simulating the fish of the pair that discharges at a faster rate whenever the two trains were close to discharge simultaneously. The number of double coincidences (i.e., simultaneous discharges occurring in two successive firing cycles) of the two simulated trains was used to measure the efficiency of the jamming avoidance. This quantity was evaluated separately as a function of the autocorrelation level and amplitude of the simulated variability, in realizations with and without jamming avoidance response. Only if jamming avoidance response was included in the simulation have we found that (i) the number of coincidences decreased with the increasing of the autocorrelation and (ii) the increase in the amplitude determined a growth of the coincidence number at a rate that is inversely proportional to the autocorrelation level. We argue that the persistent correlations of the fish variability constitute an adaptation that improves the efficiency of transient interval shortenings as a jamming avoidance strategy. The long autocorrelation time prevents the disruption of the jamming avoidance performance due to increases in the variability amplitude.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D004557	Electric Organ	In about 250 species of electric fishes, modified muscle fibers forming disklike multinucleate plates arranged in stacks like batteries in series and embedded in a gelatinous matrix. A large torpedo ray may have half a million plates. Muscles in different parts of the body may be modified, i.e., the trunk and tail in the electric eel, the hyobranchial apparatus in the electric ray, and extrinsic eye muscles in the stargazers. Powerful electric organs emit pulses in brief bursts several times a second. They serve to stun prey and ward off predators. A large torpedo ray can produce of shock of more than 200 volts, capable of stunning a human. (Storer et al., General Zoology, 6th ed, p672)	Electric Organs,Organ, Electric,Organs, Electric
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D023702	Gymnotiformes	An order of neotropical electric fish found chiefly in the waters of South America. They continually emit weak electric discharges, which they use in object location and communication. A most popular species of research interest is the electric eel, ELECTROPHORUS electricus.	Eigenmannia,Gymnotid,Gymnotidae,Eigenmannias,Gymnotids