Two Electric Fish in a Tank

This data is provided by carl hopkins and illustrates the power of the peak frequency measurement in preparations involving clear discharges with varrying pulse widths. In this example, two fish with distinctly different pulse width discharges were swimming relative to a recording element causing a large variation in spike amplitude. While the amplitude measurement could not clearly separate the two fish, a measure of the peak frequency of the discharge pulse created an orthogonal space where the two fish were obviously separated at all times. This also illustrates the power of g-PRIME to handle large data files (5 minutes in this case) and calculate thousands of event parameters fairly rapidly.

Mildly electric fish use Electric Organ Discharges (EODs) to map the conductivity of their environments as a form of perception. This is a wonderful example of an evolutionary solution to a problem of perception in mirky (low visual distance) fast moving (chemical queues are useless) waters. The discharges have characteristic shape and frequency depending on the fish. The center frequency of the discharge may be modified in order to prevent interference with nearby fish on a similar frequency and it may also be modified in order to communicate about its environment or in a courtship display.

Raw Data Files

• ptp.daq (12MB) - 5 minutes of data from a tank with one male electric fish. 100 seconds into the recording, a female fish is introduced and courtship behavior is observed -- .wav (48 MB)

An illustration of the peak frequency of the electric organ discharges (EODs) of two electric fish in a complex interaction. Signal amplitudes varry greatly as the fish swim about the tank chasing one another. Amplitude of signal varies with proximity to the recording electrodes in the water. Frequency (shape) of the pulse is constant, however, for a given animal. The fish will even modify the frequency of their dischargest to separate from one another. Here, the female displays a high frequency spread of pulses in response to the male's lower frequency discharges.

1. Load T85_24_BBTP_dyadic_interaction.daq into the analysis interface. Select channel 1. Channel 2 of this file is audio commentary of the experiment.
2. Activate threshold 1 and set the threshold to 0.034V. Hit calculate
3. Progress bars should display indicating the various stages of the analysis computation
4. Select a display of peak frequency vs time to see the distinct differences between the pulse content of the male and female spikes
5. See how the amplitude information varies greatly over the recording while the frequency display is consistant for each fish