information research group publications EOD machine lab business


About our work

Research Projects

Research Approaches

Electric Fish Primer

Electric fish movie

Electric Fish Signals

Electric Field Animations

Lab Opportunities

Directions to the Lab

Further information

 

Electric Field and Potential Animations

Brief introduction

Weakly electric fish generate weak (<0.5 V/cm) high frequency (0.1-10 kHz) electric fields which they use to locate and identify nearby objects and to communicate with other electric fish. The electric fields are produced in brief pulsed discharges from specialized tissues in the electric organ. These electric organ discharges are called EODs. Some fish produce intermittent EODs ("pulse fishes") while others produce continuous EODs ("wave fishes").

We have measured with a robotic microvoltmeter the electric organ discharges (EODs) of these fish at high temporal and spatial resolution. We have assembled the EOD measurements as pseudocolor QuickTime movies in which color represents positive and negative electric potential:

positive charge : warmer colors (green to red)
zero volts DC : light blue
negative charge : cooler colors (blue to violet)

Because the potential amplitudes vary over several orders of magnitude from near the tail to the far field, the color scale saturates (red and violet) or clips the peaks, so finer details of the far field structure are apparent.

The movies are shown in very slow "motion". If your computer is fast enough to show them at their programmed frame rate, then the movies appear at between 1/1500 and 1/5000 of their natural duration.

Credits

These movies are generated from measurements of live fish conducted by Drs. Brian Rasnow, Christopher Assad, and Philip Stoddard. To give us proper credit for our work, we ask that you please cite the papers listed by each species, rather than this website.


List of animations available at this site:

gymnotiform fishes with pulse EODs

Brachyhypopomus walteri

B_walteri.mov color Quicktime movie of electric potential

Stoddard PK, Rasnow B, Assad C. (1999)
Electric fields of the gymnotiform fishes: III. Brachyhypopomus.
J. Comp. Physiol. A, 184:609-630.

Brachyhypopomus beebei

B_beebei.mov color QuickTime movie of electric potential

Stoddard PK, Rasnow B, Assad C. (1999)
Electric fields of the gymnotiform fishes: III. Brachyhypopomus.
J. Comp. Physiol. A, 184:609-630.

Brachyhypopomus pinnicaudatus

B_pinni_male.mov color QuickTime movie of electric potential
B_pinni_female_bw.mov greyscale QuickTime movie of electric potential

Stoddard PK, Rasnow B, Assad C. (1999)
Electric fields of the gymnotiform fishes: III. Brachyhypopomus.
J. Comp. Physiol. A, 184:609-630.

Gymnotus sp. (general "carapo" type from Iquitos, but not carapo proper)

Gymnotus_sp.mov color Quicktime movie of electric potential.
Unpublished.

Gymnotus cylindricus from Costa Rica

G_cylindricus.mov color Quicktime movie of electric potential.
Unpublished.

 

gymnotiform fishes with wave EODs

Eigenmannia sp. (Glass Knifefish)

Eigenmannia.mov color QuickTime movie of electric potential

Assad C, Rasnow B, Stoddard PK, Bower JM. (1998)
Electric fields of the gymnotiform fishes: II. Eigenmannia.
Journal of Comparative Physiology A. 183(4):419-432

Apteronotus leptorhynchus (Brown Ghost Knifefish)

A_leptorhynchus.mov color QuickTime movie of electric potential.

Rasnow B, Bower JM (1996)
The electric organ discharges of the gymnotiform fishes: I. Apteronotus leptorhynchus. J Comp Physiol A 178:383:396

Apteronotus albifrons (Black Ghost Knifefish)

A_albifrons.mov color QuickTime movie of electric potential.