Some Possible Limits on the Minimum Electrical Signals of Biological Significance

  • Frank S. Barnes
  • Mohammad Seyed-Madani


It is of interest to consider what might be the lowest-level electric and magnetic signals that are biologically important. This is important in helping to decide what experiments are worth performing, as well as in setting safety standards. Deciding what the lowest-level fields or currents are is not a simple issue, because the biological effects of an externally applied electric field or current may be dependent on the particular cell or organ to which they are applied as well as on the time of their application. The amplitude of the current, the field direction, the pulse length, the frequency and the shape of the signal may all be important when the system is nonlinear or time-dependent. Thus two current pulses of the same size and shape may have quite different effects on the firing rate of a pace-maker cell, depending on the point of the firing cycle at which they are injected or on the closeness of the repetition rate to the natural firing rate. In addition, we can reasonably expect that the minimum signal for which we can detect a biological change will decrease as our measuring techniques improve, and as our biological understanding improves.


Firing Rate Noise Voltage Squid Axon Mylar Film Minimum Signal Level 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    A. Yariv, “Optical Electronics”, third edition, 1985. New York: olt Rinehart Winston.Google Scholar
  2. 2.
    F.N. Hooge, “1/f Noise”, Physica 83B (1976), pp. 14–23.Google Scholar
  3. 3.
    M.S. Keshner, “1/f Noise”, Proc. IEEE 70, No. 3, (March 1982), pp. 212–218.Google Scholar
  4. 4.
    H.M. Fishman, “Material from the Internal Surface of Squid Axon Exhibits Excess Noise,” BioPhys J 35, (July 1981), pp. 249–255.PubMedCrossRefGoogle Scholar
  5. 5.
    D.L. Dorset, H.M. Fishman, “Excess Electrical Noise During Current Flow Through Porous Membranes Separating Ionic Solutions,” J. Membrane Biol. 21, pp. 291–301 (1975).CrossRefGoogle Scholar
  6. 6.
    A.A. Verveen, H.E. Derksen, “Fluctuation Phenomena in Nerve Membrane,” Proc. IEEE 56, No. 6, (June 1968), pp. 906–916.CrossRefGoogle Scholar
  7. 7.
    M. Ten Hoopen and A.A. Verveen, “Nerve-Model Experiments on Fluctuation in Excitability,” in Nerve, Brain and Memory Models, ed. N. Wiener and J.P. Schade (Progress in Brain Research, Vol. 2). New York: Elsevier, 1963, pp, 8–21.Google Scholar
  8. 8.
    E. Siebenga, A. Meyer, A.A. Verveen, “Membrane Shot Noise in Electrically Depolarized Nodes of Ranvier,” Pflüger Arch 341, pp. 87–96.Google Scholar
  9. 9.
    E. Smith, “The Natural Radio Noise Source Environment,” IEEE EMC Symp., Sept. 1982.Google Scholar
  10. 10.
    F. Conti, E. Neher, “Single channel recording of K+ currents in squid axons”, Nature 285 (1980), pp. 140–143.PubMedCrossRefGoogle Scholar
  11. 11.
    F. Sigworth, E. Neher, “Single Na+ Channel Currents Observed in Cultured Rat Muscle Cells,” Nature 287, (1980), pp. 447–449.PubMedCrossRefGoogle Scholar
  12. 12.
    “Nonlinear Microwave Bioeffects on Isolated Neurons of Aplysia,” M.S. thesis by Joseph D. Forster, University of Colorado, Boulder, Department of Electrical Engineering, 1981.Google Scholar
  13. 13.
    “Nerve-Model Experiments on Fluctuation in Excitability,” M. Ten Hoopen and A.A. Verveen in Nerve, Brain and Memory Models, ed. N. Wiener and J.P. Schade (Progress in Brain Research, Vol. 2). New York: Elsevier, 1963, pp. 8-21.Google Scholar
  14. 14.
    H. Wachtel, “Firing-pattern changes and transmembrane currents produced by extremely low frequency fields in pacemaker neurons, in Proc. 18th Annu. Hanford Life Sci. Symp., Technical Information Center, Department of Energy, Richland, Wash., 1978, p. 132.Google Scholar
  15. 15.
    J. Bernhardt, “The Direct Influence of Electromagnetic Fields on Nerve-and Muscle Cells of Man Within the Frequency Range of 1 Hz to 30 MHz,” Rad. and Environm. Biophys. 16, (1979), pp. 309–323.CrossRefGoogle Scholar
  16. 16.
    L.F, Jaffe, “The role of ionic currents in establishing developmental pattern,” Philos. Trans. R. Soc. London, Ser. B 295, (1981), p. 553.PubMedCrossRefGoogle Scholar
  17. 17.
    A.A. Verveen, L.J. DeFelice, “Membrane Noise,” Progress in Biophysics and Molecular Biology 28, (1974), p. 189.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1987

Authors and Affiliations

  • Frank S. Barnes
    • 1
  • Mohammad Seyed-Madani
    • 1
  1. 1.Dept. of Electrical & Computer EngineeringUniversity of ColoradoBoulderUSA

Personalised recommendations