Behavioral Neuroscience Summers

Electric Fish and JAR Behavior Afferent Path of Electroreception Control of Electric Organ Discharge Efferent Output producing EOD Jamming Avoidance Response

Glutamate GABA Acetylcholine Electric Fish Figures Electric Fish Circuitry Acronyms/Abbreviations    end

Jamming

Biogeography of Electric Fish

The figure also shows the location of the electric organ in each fish, and a sample of the waveform of the electric organ discharge
Comparing South America and Africa

Weakly electric fish from South America, Sternarchorhynchus mormyrus, and Africa, Campylomormyrus phantasticus. Both fish evolved the ability to generate and sense electric fields. These two species also independently evolved curved jaws for bottom feeding. Electric discharges for each species are indicated. Images courtesy of Carl D. Hopkins and John Sullivan.

Evolution of Weakly Electric Fish

Electroreception is widespread among vertebrates, with cases in all classes of fishes, two orders of amphibians and even the duck-billed platypus. This 'exotic' sense seems to be an ancestral vertebrate trait, as it is present in lampreys and cartilaginous fishes. Electroreception has evolved a number of times during vertebrate evolution. Electroreceptors vary in sensitivity (from 0.005 mV cm^-1 to >0.1 mV cm^-1) and frequency sensitivity (near DC (direct current) to >15 kHz). All electroreceptive animals have ampullary receptors, which are highly sensitive and best excited by very low frequencies (less than 30 Hz). Other electroreceptor types are found in most electrogenic species. Electrogenic fish produce electric signals by discharging their electric organs, which consist of columns of modified muscle cells (electrocytes). Some organs generate strong discharges (hundreds of volts) that are useful for stunning prey, whereas others produce weak discharges (millivolts) that are used for social communication and electrolocation. Species that have electric organs of the latter type produce either intermittent (pulse species) or periodic (wave species) discharges. Both types of weakly-electric fish also have electroreceptors that are tuned to the species-specific higher frequencies found in their discharges. b reproduced, with permission, from Ref. 19 © (1999) Company of Biologists. Rose 04 Nature Reviews Neuroscience 5, 943-951
African Mormyrids


Strongly Electric Fish
1) Oceanic

Torpedo nobiliana - Electric Ray

Torpedo marmorata - Marbled Electric Ray 2) Rivers and Swamps of South America
Tanya Dewey, Animal Diversity Web, University of Michigan Museum of Zoology
Electrophorus electricus (electric eel)
3) Rivers of Africa
Stan Shebs
Malapterurus electricus - Electric Catfish

Weakly Electric Fish
1) South America

Apteronotus albifrons - Black Ghost Knifefish

Eigenmannia virescens - Glass Knifefish

Sternopygus macurus - Gold-lined knifefish

2) Africa

Gymnarchus niloticus - Nile Aba Aba Knifefish


Electric Organs
1) Elephantnose EO location

2) Serial capacitors



Electric Fields



References on the WWW:
http://www.sbg.ac.at/ipk/avstudio/pierofun/ray/eod.htm

Electric Organ Discharge:
http://instruct1.cit.cornell.edu/courses/bionb420.07/aakhavan/MW1/EOD.html
http://www.biology-online.org/dictionary/electric_organ
http://www.elasmo-research.org/education/topics/p_batteries.htm
http://sci-toys.com/scitoys/scitoys/biology/electric_fish/electric_fish.html
http://www.use.hcn.com.au/portals/shared/subject.%60Electric%20Organ%60/home.html
Electroreception:
http://www.hawaii.edu/HIMB/sharklab/hammerheads/electroreception.htm
http://www.amnh.org/learn/pd/sharks_rays/rfl_dissection/
http://research.umbc.edu/~cole/electro.htm#info

Electric fish:
http://www.people.virginia.edu/~mk3u/mk_lab/electric_fish_E.htm
http://www.bbc.co.uk/dna/h2g2/alabaster/A735004
http://www.utexas.edu/neuroscience/Neurobiology/HaroldZakon/research.html
http://www.bio.davidson.edu/people/midorcas/animalphysiology/websites/2003/Wilson/Stunning.htm
http://www.gulfspecimen.org/SharksRays.html
Electric Rays: http://www.funkandwagnalls.com/encyclopedia/low/articles/r/r022000297f.html
http://www.tpwd.state.tx.us/expltx/eft/gulf/cspecies/lesserelectricray.htm
http://www.sms.si.edu/IRLFieldGuide/Narcin_brasil.htm
http://www.hammer-time.com/lesserray.htm
http://www.wgn.net/~fabio/gallery/gallery1.htm
http://web.ukonline.co.uk/aquarium/pages/electricray.html
http://www.gulfspecimen.org/Electric-Ray.html

Family of the elecrtric rays:
http://benthos.cox.miami.edu/reef/taxonomy/family71.html
http://reef.org/survey/family/71.htm

Marbled Electric Ray:
http://web.ukonline.co.uk/aquarium/pages/marbledelectricray.html
http://www.mermaid1.demon.co.uk/body_creature9902.htm

Torpedo californica:
http://www.mbayaq.org/efc/living_species/print.asp?inhab=510
http://www.elasmo-research.org/education/shark_profiles/torpediniformes.htm
http://saintbrendan.com/cdnmay/marinlf5.html
http://www.flmnh.ufl.edu/fish/Gallery/Descript/Peray/Peray.html

Torpedo electric organ
http://www.heuserlab.wustl.edu/TorpedoEELink.html
http://www.csulb.edu/~zedmason/emprojects/MATHEW/mathew.html

Rays - what's that?
http://www.enchantedlearning.com/subjects/sharks/rays/

Fish Species database: http://www.fishbase.org/search.cfm