Ontogeny of the electric organ discharge and the electric organ in the weakly electric pulse fish Brachyhypopomus pinnicaudatus (Hypopomidae, Gymnotiformes)

1997 ◽  
Vol 181 (2) ◽  
pp. 111-119 ◽  
Author(s):  
C. R. Franchina
Keyword(s):  
Electric Organ Discharge ◽  
Electric Pulse ◽  
Electric Organ ◽  
Weakly Electric ◽  
Brachyhypopomus Pinnicaudatus

The electric image in weakly electric fish: perception of objects of complex impedance

2000 ◽  
Vol 203 (3) ◽  
pp. 481-492 ◽  
Author(s):  
R. Budelli ◽  
A.A. Caputi
Keyword(s):  
Linear Function ◽  
Electric Organ Discharge ◽  
Amplitude Ratio ◽  
Complex Impedance ◽  
Electric Organ ◽  
Weakly Electric Fish ◽  
Peak Amplitude ◽  
Electrical Characteristics ◽  
Electric Image ◽  
Weakly Electric

Weakly electric fish explore the environment using electrolocation. They produce an electric field that is detected by cutaneous electroreceptors; external objects distort the field, thus generating an electric image. The electric image of objects of complex impedance was investigated using a realistic model, which was able to reproduce previous experimental data. The transcutaneous voltage in the presence of an elementary object is modulated in amplitude and waveform on the skin. Amplitude modulation (measured as the relative change in the local peak-to-peak amplitude) consists of a ‘Mexican hat’ profile whose maximum relative slope depends on the distance of the fish from the object. Waveform modulation depends on both the distance and the electrical characteristics of the object. Changes in waveform are indicated by the amplitude ratio of the larger positive and negative phases of the local electric organ discharge on the skin. Using the peak-to-peak amplitude and the positive-to-negative amplitude ratio of this discharge, a perceptual space can be defined and correlated with the capacitance and resistance of the object. When the object is moved away, the perceptual space is reduced but keeps the same proportions (homothetically): for a given object, the positive-to-negative amplitude ratio is a linear function of the peak-to-peak amplitude. This linear function depends on the electrical characteristics of the object. However, there are ‘families’ of objects with different electrical characteristics that produce changes in the parameters of the local electric organ discharge that are related by the same linear function. We propose that these functions code the perceptual properties of an object related to its impedance.

Plasticity of the electric organ discharge waveform of male Brachyhypopomus pinnicaudatus . II. Social effects

2001 ◽  
Vol 187 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Cheryl R. Franchina ◽  
Vielka L. Salazar ◽  
Claude-Henry Volmar ◽  
Philip K. Stoddard
Keyword(s):  
Electric Organ Discharge ◽  
Electric Organ ◽  
Social Effects ◽  
Brachyhypopomus Pinnicaudatus

Evoked chirping in the weakly electric fish Apteronotus leptorhynchus: a quantitative biophysical analysis

1993 ◽  
Vol 71 (11) ◽  
pp. 2301-2310 ◽  
Author(s):  
Günther K. H. Zupanc ◽  
Leonard Maler
Keyword(s):  
Electric Organ Discharge ◽  
Electric Organ ◽  
Stimulus Onset ◽  
Weakly Electric Fish ◽  
Apteronotus Leptorhynchus ◽  
Biophysical Analysis ◽  
Absolute Amplitude ◽  
Electric Organ Discharges ◽  
Gymnotiform Fish ◽  
Weakly Electric

Apteronotus leptorhynchus, a gymnotiform fish, produces highly regular electric organ discharges of 600–1000 Hz. Short-term modulations of the electric organ discharge ("chirps") were elicited by imitating the discharges of neighboring fish. Chirps displayed an increase in frequency of approximately 100 Hz, a duration of about 15 ms, and an absolute amplitude of 0.5–2 mV. Since, similar to natural conditions, chirps summated with the beat caused by interference of the fish's own electric organ discharge and the imitating discharge, the size and shape of the chirp's amplitude envelope varied greatly according to its phase relative to the beat cycle; however, the frequency of the chirp amplitude modulation was always 50–100 Hz. All 21 males examined chirped, but their rate of chirping varied considerably (range 2–59 chirps/30 s; mean 22 chirps/30 s). In contrast, only one out of nine females chirped (mean 0.25 chirps/30 s). The latency between stimulus onset and first chirp was variable and often long (range 1.0–25.0 s; median 3.3 s). We propose that chirps are not a sensory reflex but a communicatory behavior regulated by hypothalamic peptidergic input.

scholarly journals Electrical signalling of dominance in a wild population of electric fish

2010 ◽  
Vol 7 (2) ◽  
pp. 197-200 ◽  
Author(s):  
Vincent Fugère ◽  
Hernán Ortega ◽  
Rüdiger Krahe
Keyword(s):  
High Frequency ◽  
Electric Fish ◽  
Electric Organ Discharge ◽  
Low Frequency ◽  
Electric Organ ◽  
Weakly Electric Fish ◽  
Dominance Status ◽  
Strong Positive Relationship ◽  
Electrical Signalling ◽  
Weakly Electric

Animals often use signals to communicate their dominance status and avoid the costs of combat. We investigated whether the frequency of the electric organ discharge (EOD) of the weakly electric fish, Sternarchorhynchus sp., signals the dominance status of individuals. We correlated EOD frequency with body size and found a strong positive relationship. We then performed a competition experiment in which we found that higher frequency individuals were dominant over lower frequency ones. Finally, we conducted an electrical playback experiment and found that subjects more readily approached and attacked the stimulus electrodes when they played low-frequency signals than high-frequency ones. We propose that EOD frequency communicates dominance status in this gymnotiform species.

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