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.