... of the JAR behavior in terms of a dynamical system model has not been achieved at least in part due to the fact that ‘avoidance’ behaviors are both intrinsically unstable and nonlinear. We overcame the instability of the JAR in Eigenmannia virescens by closing a feedback loop around the behavioral response...

... the possibility that social context creates envelopes that drive behavior. When Eigenmannia virescens are in groups of three or more, the interactions between their pseudo-sinusoidal electric fields can generate ‘social envelopes’. We developed a simple mathematical prediction for how fish might respond...

... Gnathonemus petersii Eigenmannia It was only in the early 1950s that Hans Lissmann from the University of Cambridge demonstrated that certain African fish produce weak electric signals in the water using their electric organ ( Lissmann, 1951 ). Lissmann and Machin (1958) later employed...

... waveforms. The EOD of Eigenmannia is sexually dimorphic in waveform and in the intensity of its higher harmonics. In a go/no go paradigm, trained food-rewarded fish discriminated between these waveforms, and naive (untrained) fish showed a significant preference. To determine whether spectral or waveform...

... fish of the genus Eigenmannia . The roles of passive and active membrane properties of neurons, and frequency-dependent gain-control mechanisms are discussed. * e-mail: [email protected] 22 01 1999 21 04 1999 © 1999 by Company of Biologists 1999...

...Yumi Takizawa; Gary J. Rose; Masashi Kawasaki ABSTRACT The algorithm for the control of the jamming avoidance response (JAR) of Eigenmannia has been the subject of debate for over two decades. Two competing theories have been proposed to explain how fish determine the correct direction to shift...

... of the more usual feedforward modeling of neuronal responses ( Fig. 1 ) and which is described next. Tuberous electroreceptor organs are distributed in the skin of Eigenmannia with highest density in the head region. They are contacted by two types of sensory afferent fibers which relay electroreceptive...

... in Eigenmannia , in contrast, are controlled via a pathway running from the TSd through the ventral portion of the nucleus electrosensorius complex (nE↓) and the mesencephalic SPPn primarily to relay cells in the pacemaker nucleus ( Fig. 1A ). Neurons in the nE↓, when stimulated with L-glutamate, cause gradual...

...Bernd Kramer; Ivo Kaunzinger ABSTRACT Eigenmannia’s frequency and intensity discrimination thresholds were determined for a range of seven frequencies (50–1700Hz), centered on a fish’s individual discharge frequency, using a conditioned go/no-go paradigm. The threshold criterion was ‘50% correct...

...BERND KRAMER; BRUNHILDE OTTO Eigenmannia lineata is a tropical South American gymnotiform fish that is both electrogenic and electroreceptive. Its electric organ generates a constant-frequency wave discharge (EOD) that is sexually dimorphic in waveform and harmonic content. Eigenmannia...

...Bernd Kramer ABSTRACT Eigenmannia’ s, jamming avoidance response (JAR) is a frequency change of its electric organ discharge (EOD) in response to an electric stimulus of similar frequency (small ΔF; ΔF = F Fish – F Stim ). It is assumed that the response to an unclamped stimulus, ΔR = F Response...

...Bernd Kramer ABSTRACT The present report shows an intraspecific, sexually dimorphic variation in harmonic content and waveform, as well as intensity, of the Electric Organ Discharges (EODs) in the green knife fish, Eigenmannia ( Figs 2 , 11 ). There is a close correlation between harmonic content...