IM7'ESTIGATION OF ELECTRIC FISHES 28 February 1973 CONTENTS INTRODUCTION ........................... 2. TECHI\IICAL DISCUSSION ..................... 2 3. STATEMENT OF WORK ....................... 5 4. PRICE AND CONTRACTUAL INFORMATION ........ 8 5. PERS.ONNEL ............................. 10 REFERENCES ................... 12 1. M"TRODUCTION In a previous proposal, it was stated that the relationship between electroreceptors in the pattern recognition process of electric fish would be studied. In a Midterm Report of September 1972, the phasic tuberous asynchronic electroreceptors and the synchronous tonic ampullary electro- receptors of the -Sternarchus albif2rons, a freshwater South American weak electric fish were described. The tonic asynchronous ampullary electro- receptors of the same fish species were described previously. Measure- ments were made and reported. The studies on Gymnarchus niloticus, a freshwater African weak electric fish., were continued, as were studies of the effect of different anaesthe'Lics on the el-e''ctrical activity of electric fishes. The effect of D- tubocur,.rine and the counteref'Lect of neostia-mine on Sternarchus albifrons ,%,,.,ere also assessed-. Three mormyrids (Gnathonemus petersii) were obtained, a fresh- water African weak electric fish supposed to be the most intelliaent fish (sic). The brain/body weight-ratio is close to that of human beings. Pre- viously, one fish of this species was trained to jump through a circle over the water in order to get its food. Studies of the electric activity of these fishes Niill yield added information on pattern reco-nition ability of electric fishes. Based upon data generated by these studies, we now propose to generate design and test concepts for physical analoas of the electroreceptors 9 of electric fish to be used in subsequent studies of underwater object detection, identification, and position. These sensor analog simulation tests will be planiicd to be performed in a plastic water tank of 18 feet diameter. 2. TECIINICAL DISCUSSION From previous and oncroinc, investimations, it was determined that Sternarclius albifrons, a South American freshwater hich-frequency weak electric fish, has three kinds of electroreceptors: 1. synchronous tonic ampullary electric sensors 2. asynchronous tonic ampullary electric sensors 2 3. asynchronous phasic tuberous electric sensors Microelectrode recordino-s were made from these receptors. The fish was anaesthetized with tricaine methanesulfonate (Finquel "Ayerst") and cura- rized with D-tubocurarine. Subsequently,. neostic'mine was used to counter- act the loncr-term effect of curare. A search for an anaesthetic that will not affect th2e frequency and amplitude of the electric sicrnals emitted by electric fish has been made. This study is in progress and preliminary results indicate that thiopental sodium may not affect the electric sicrnal of Sternarchus albifrons. Both ampullary and tuberous electric sensors are autorhythmic. Two out of three kinds of electric sensors act independently of the main electric organ. This means that we deal with 2three transmitting systems: a main orcan and two secondary represented by the autorhythmic activity. There are also three kinds of electroreceptors, two of which are transmitters and receptors at the same time, and eacli of them may have some finer subdivisions with re-ard to sensitivity, amplitude, frequency, latency and habituation. These electroreceoptors are part of the "lateralis sy5stem" of the fish and the otlier orc,,-tns related to this system like the lateral line receptors and the free neurom,,ists are certainly playing an important role in pattern recorrnition. 2 s,mol-cu-c 1-coisAtid aill 9uiqljz)sop XOJ STS'CQ r, PDPIAOad o,%oq-c pollo sr, sule4sAs S.losuas tlslj olilo olo Jo S.X@1140 PU'C S@PII'U'OV Aq S6TPnIS -olurls tIO142-CZTllq-CIS Irnsn aql xo4jz p@uu-eld St Apnls puc paui-c4qo aq ut:z) 'qstj oial-Dela piaaul -jou.i Aouenba.Tj-A@.ol a@4-cA@ilsa ij u-E3ijIV uc 'llsia4ad sntuauotl;-cuf) -saic)a2ds ;jui-es xiatI4 Jo saaqtu@Tz tilTA,, 94-cziunT-UT-Uoz) ol s-noi;ollu snT4oiEuut,@9 JO A4111q'C DT41 PDI'E.1-4SUOU.I@p OA-Utl S@Tpnls SMOIA@.XA -uoil-cool 4oalqo pu-e UOII-E'UTA,CU UT. 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Continuation of this work can establish physical analogs for other electroreceptors and sensory receptors of the "lateralis system" of electric fishes. 2 s oh Microelectrode recording , histology, licr t microscopy,. electro- microscopy, and scannin- electronmicroscopy can be used to clarify the establishment of the physical analogs. Some studies on the sensitivity threshold of electric fishes to electric stimuli were made by This proposed study intends 2to extend this work. An extensive study of the sensitivity of different species of electric fishes to electric stimuli in the presence of noise and without noise will be made to find out which of the different types of sensory systems of the different species is most ef- fective in locatina and identifyinc, objects underwater. For these experiments, we will use an instrumented pool2 facility. The distance at which an electric fish can identify movina and stationary objects and to communicate .vith specimens of its own species can be de- ducted from the distance, the composition and size of the objects presented to the subject and of the distance of back-playing electrodes and the applied attenuation to the sic-nal. By addina- specific kinds and amplitudes of no2ise we will be able to find out how well the fish can extract the si(rnal from noise. Having all of the previously mentioned data, we can proceed to the establishment of an underwater pattern recognition diacrram. The established 0 physical analo-s of electric sensors and cross correlation will be proposed 3 as a means for ideiitif in(r objects. y 4 3. STATEME'@,TT OF WORK /will provide the personnel, services and material necessary to conduct an investigation O'L@ electric fishes. The tasks for Phase I and Phase II will be performed as outlined below. PIIASE I 1. Investigate the ability of freshwate2r electric fishes to recoonize patterns under water and how effectively they can differentiate between different parameters when navic-ating. It is proposed to use three or four of the following kinds of freshwater weak electric fishes: a. Sternarchus albifrons, hic-h signal rate electric fish 2 with its frequency nced only by change in the tank water temperature; region of oricin - subtropical,, tropical and equatorial South America. b. Gymnarchus niloticus, medium fixed signal rate electric fish with its frequency not influenced by chancre of tank water temperature; region of origin - subtropical, 2 tropical, and equatorial Africa. C. Gymnotus carapo, variable medium signal rate electric ri-sh, re7;-'o@n of@orig@n - subtropical, tropical, and t;l equatorial South America. d. Gnathonemus petersii, a variable low signal rate electric 2 fish o t e mormyridae family; region of origin - sub- tropical, tropical, and equatorial Africa. 2. Microelectrode recording, histology, ii-ht microscopy, electro- t:l microscopy and scanning electromicroscopy will be used as ne- cessary to elucid,.ite and establish the interrelation of electric receptors. 3. Report. A report of the six months' study will be submitted at the end of Pli,.ise I. 5 PHASE II The threshold of electric si gn.11 stimuli eliciting a behavioral response in electric fishes will be investic,,r,,Ited for: a. fishe's onvn Si-nal recorded on magnetic tape and played back and attenuated. 2 b. same species but another subject fish's electric signal recorded on magnetic tape, played back and attenuated c. sinusoidal electric sional with same repetition rate as c@ the fish's own signal or slia t;l htly chanced a2nd attenuated d. signals as in (1) and (2) but with a noise source like gaussian noise and varying amplitude will be added through another pair of electrodes in the same water tank. These e.%-periments will be carried out in a special round tank of 18 feet diameter by 22 feet high and placed in a special tank facility. 2. From all these results, the distance will be calculated at which an electric fish could detect its own or another elec#.-ric sicnal considerinc, the attenuation, the distortion of the signal in water tzp I 2 and eventually the added noise. 3. Physical analogs will be established for some of the electro- receptors, displacement receptors, and other lateral line type of receptors. 4. A diagram for an underwater pattern recognition simulation of the electric fish's electric sensors system, usin- their 2 physical analogs and a special cross -correlation data pro- cessin-, will be sul)i-nitted. A special iiistruniented under- water pool facility and computer simul,,ttinc, equipment will be considered for use for this proposition. 5. Reports. Financial monthly reports will be submitted. A 0 final report will be furnished one year after contract award. The scliedule for the proposed research is outlined in Fir. 5 Nvitli the estiiiiited time for cirryin- out each liase. p 6 CALENDAR MONTIIS TASIC 2 3 4 5 6 7 8 9 lo ii 12 1. Investigate pattern recognition ability and v navigation abilit2y of three or four different electric fish species. 2. Investigate the interrelation of electric receptors. p-q 3. Report 1. Establish the threshold of electric s,@timuli v clicitiiig a behavioral response In electric fish under different condi2tions. 2. Establish the distance at Nvldch electric sigmals can be detected by electric fish. rn 3. Establish physical analogs of the electric IV' receptors. 4. Design a diagram for an undenvater simu- lation of the fish's electrosensory system. 7 5. Final report Fig. 5. Program Schedule. 4. PRICE AND CONTRACTUAL =ORIIATION sur,c,ests that the proposed program be conducted over a one-year period under a cost-plus fixed-fee contract. The estimated costs for this program are shown at the end of this section. The lal)or costs used in this proposal are based upon the current averaae rate of the level of2 personnel e.%-pected to be employed in the pro- posed effort. No premium for direct overtime expense has been included in this proposal. The overhead rate used in this proposal is provisional and con- sists of all indirect costs and is adjusted for assumed unallowable costs. Overhead rates will be adjusted at the end of the fiscal year 2 to actual costs excludin(r 0 disallo,.vables, as determined by Government audit. is under the audit cognizance of the Defense Contract Audit Ac,,@ncy, Unless previously ivithdranvn in writing, 'this proposal ,vill remain valid for ninety days from the 9date on the cover. 8 ESTMLI@TE- D COST FOR A TWE, LVE- -MONTH PROGRAM Man-Hours PERSONNEL COSTS Scientist 41 1210 Scientist 23 40 Scientist 12 100 Technical Typist 96 OVER2HEAD @ FPJ.LNGE BENEFITS @ TRAVEL: Ph,-zse I Phase II MATERIALS: Phase I Phase II TOTAL DIRE, CT COST & OVERHEAD GENERAL & ADMINISTRANVE EXPENSE @ TOTAL ESTIIVTATED COST FIXED FEE TOTAL ESTIIMATED COST PLUS2 FIXED FEE 9