PROPOSAL for a STUDY'OF THE SENSITIVITY AND RESPOf4SE OF WEAKLY ELECTRIC FISH TO STATIC AND PULSO -4liAGNETIC FIELDS submitted by the AIML PROPOSAL 'iSE STUDY OF TliE SEt'ISITIVITY i@fID rESPOi OF IIEAI(LY ELECTRIC FISfl TO ST'ATIC A14D PULSED i-lAGIIETIC FIELDS Backqt-ound. 2 rticularly in the various spe- The study of bioelectrogenesis, pa cies bf electric fish, has been of increasing scientific concern in recent years. This interest stems primarily from the potential use- .fulness'of research in.this area in contributing to our understand- ing of i number of fundamental and significant problems. By defini@g 2 the electric fish's unique sensitivity 'to electric and magnetic fields, and how it codes and utilizes such sensory information in its detec- ,tion and navigation behavior, current evidenob is providing a more complete concept of such basic questions as migration and territorial- ity, and is leading toward the development of various bionic devices in the form of under@.jater sensors and po2wer sources. In addition, knowledge of the effects of magnetic and electric fields on physio- logical and behavioral processes iias assumed great importance in viel't of man's exposure to drastic changes in such stimuli during space @travel. Living things produce a changing electric fip-ll at and near the surface of their. bodies; all fish, being sheathed in a conducti2ve substance and living in a conductive medium, produce an electric field that may be detected at relatively great distances. However, there are certain fish which produce electric fields exceeding the norm by hundreds or thousands of degrees of magnitude. The electric eels of the Amazon can produce bursts in excess of 600 volts. Other electric fish, i.e., weakly electric fish, produce continuous field2s measured only in millivolts, but by means of interpreting distortions in these fields are able to sense and navigate through their environment to a degree comparable to that of other species in which vision is used for these purposes. The weakly electric fish,,having very poorly de- veloped visual abilities, must depend on information acquired through their electric fields in order to survive. 2 The magnetic field is a form of energy to which all plants and animals are exposed. Its influence on living systems, however, is subtle and not well understood. One approach to studying the effects of magnetic fields upon behavior is through the use of an organ-ism which produces an electric field and uses it as a detection and naviga- tion qiechanism. The electric fish is just su2ch an organism, and a one- year s.tudy, .. I .i .1 of S'ternarchus albifr'o'n'-s"a-nu'-S. 'I'e'c)torhv'nchus, has demonstrated the feasibility of such @-iork. In these species, im- pulses are discharged from the tail and received by the head, which b4ecomes positive in regard to the tail. This potential difference creates an electric field about the fish's body, permitting it to de- .tect objects through distortions in the field. Several studies have shown that these fish can perceive a static (con,,tant strength) magnetic field, but only when either the organism ot- the field is in motion, therby generating a current in the fish. It was thought that the fish was responding to the current generated in itself by the magnet. However, in these experiments the magnetic field was presented al, a static field, and the sensitivity of -the fish to a pulsed field presented at various frequencies, praticularly the frequency at which the fish discharges its own electric field 2(500-1500 cps), was not investigated. Other investigators have shc@vin drastic increase in sensitivity to applied A.C. approximating the frequency of the fish's discha'rge. In addition, the strength of the field was not systematically varied in terms of the gauss level in the fish's pro- ximity, Therefore, there are considerable gaps in our knowledgq of2 the degree of sensitivity of the fish to magnetic ilields at various frequencies and strengths. @omplqted And osed Research. In order to more clearly define the weakly electric fish's sensitivity and responses to different types of magnetic fields, a study was undertaken on June 1, 1969, in which se,/eral individuals 2 of S. albifrons and S. leptorhynchus were obtained, life-support tec'Fni'@ue-s dev-eloped-, and test and recording equipment purchased and constructed. The fish were tested in a Y maze, T maze, and restraining chamber, and oscilloscope recordings.were made of their discharge patterns over time, through variations in temperature, and in response to various dru2gs including levodopa in a base-line study. Thier sensiti@ity to static and pulsed magneti-. fields exceed- ing variations in the earth's magnetic fields was observed over the following ranges of values: between I and 10 gauss with a static field; from 0.29 to 82 gauss at 60 cps; and from 10 to 20 'Ganss at frequencies of 685-1220 cps. depending on the fish's o2wn frequency. Apparent negative results were obtained with the static field; but the subjects were clearly responsive to the pulsed field at all gauss and frequency levels. In addition, a method was devised to administer the drug levodopa to the fish in order to determine the effects of this agent on their behavior. Two specimens were tested, and the influence of the drug on their 2electrical and overt behavior noted. However, the data are not complete enough to draw any firm conclusions, Since this study is currently coming to a close, and the positive results wi)ich are emerging indicate that further study should provide very meaningful results, it is hoped that the work'can be continued. It is proposed that the following lines of investigation be follow2ed: A. To determine the final absol-ute and terminal thresholds of t@e fish's perception of a static magnetic field. B. To determine the final absolute and terminal thresholds of the fish's perception of a pulsed magnetic field by varying its freq@ency and strength over a wide range of values. C. To determine the fish's sensitivity to e5lectric current, as a basis of comparison with his perception of magnetic fields. In addition, to calculate the current generated in the fish by magnetic fields, duplicate these values with an audio signal generator, and compare the results with his performance under the other conditions. III. fnabilities staff consisting of 42 full-time and 21 part-time employees and four students working for the Ph.D. degree in infoma- tion science. Of this number of employees, two have M.D.'s, three have Ph.D.'s and nine have the I-l.A. or M.S. degree or are otherwise qualified to work at the professional level., The Droposed project would be under the irection of is-a do:--toral candidate in psychology aod 'iis a graduate.' @iologist working for the M.S. degree in ecology- Laboratory facilities are available IV. Plan of Procedure. The work will be accomplished within six months from the 2 effective date of the contract. Five copies of a final report will be prepared and submitted to the contracting agency. V. @@et - 6 Months. A. Personnel. Secretary (3%) -..,-.--Total P@@sonnel B.' Fringe benefits* (16.5"I S&W) 2Indirect costs (40.00 S&@l provisional) C. Consultant fees D. Travel - local E. Reproduction & duplication F. Supplies and expendible equipment G. Equipment Total budget The total salary and wage amount shown herein provides for direct 0 labor effort in the percentages for hours expressed herein for the budget period. The fringe benefit rate is a package rate which pro- vides for several benefits including vacation and sick leave earned