Journal of Comparative Physiology A

, Volume 194, Issue 3, pp 209–220 | Cite as

Response properties of electrosensory neurons in the lateral mesencephalic nucleus of the paddlefish

  • Boris P. Chagnaud
  • Lon A. Wilkens
  • Michael H. Hofmann
Original Paper


Many fishes and amphibians are able to sense weak electric fields from prey animals or other sources. The response properties of primary afferent fibers innervating the electroreceptors and information processing at the level of the hindbrain is well investigated in a number of taxa. However, there are only a few studies in higher brain areas. We recorded from electrosensory neurons in the lateral mesencephalic nucleus (LMN) and from neurons in the dorsal octavolateral nucleus (DON) of the paddlefish. We stimulated with sine wave stimuli of different amplitudes and frequencies and with moving DC stimuli. During sinusoidal stimulation, DON units increased their firing rate during the negative cycle of the sine wave and decreased their firing rate to the positive cycle. Lateral mesencephalic nucleus units increased their rate for both half cycles of the sine wave. Lateral mesencephalic nucleus units are more sensitive than DON units, especially to small moving dipoles. Dorsal octavolateral nucleus units respond to a moving DC dipole with an increase followed by a decrease in spike rate or vice versa, depending on movement direction and dipole orientation. Lateral mesencephalic nucleus units, in contrast, increased their discharge rate for all stimuli. Any change in discharge rate of DON units is converted in the LMN to a discharge rate increase. Lateral mesencephalic nucleus units therefore appear to code the presence of a stimulus regardless of orientation and motion direction.


Electroreception Midbrain Paddlefish Motion Lateral mesencephalic nucleus 



Dorsal octavolateral nucleus


Lateral mesencephalic nucleus


Torus semicircularis



The experiments comply with the “Principles of animal care”, publication No. 86–23, revised 1985 of the National Institute of Health. This research was supported by grants from the NSF/DAAD, the National Science Foundation (IOB−0524869), and a University of Missouri Research Board grant. Paddlefish were kindly supplied by the Missouri Department of Conservation.


  1. Batschelet E (1981) The Rayleigh test. In: Batschelet E (ed) Circular statistics in biology, 1st edn. Academic, New York, pp 54–58Google Scholar
  2. Bell CC, Maler L (2005) Central neuroanatomy of electrosensory systems in fish. In: Bullock TH, Hopkins CD, Popper AN, Fay RR (eds) Electroreception. Springer, New York, pp 68–111CrossRefGoogle Scholar
  3. Bodznick D, Montgomery JC (2005) The physiology of low-frequency electrosensory systems. In: Bullock TH, Hopkins CD, Popper AN, Fay RR (eds) Electroreception. Springer, New York, pp 132–153CrossRefGoogle Scholar
  4. Goldberg JM, Brown PB (1969) Response of binaural neurons of dog superior olivary complex to dichotic stimuli: some physiological implications. J Neurophysiol 3:613–636Google Scholar
  5. Hofmann MH, Wojtenek W, Wilkens LA (2002) Central organization of the electrosensory system in the paddlefish (Polyodon spathula). J Comp Neurol 446:25–36PubMedCrossRefGoogle Scholar
  6. Hofmann MH, Falk M, Wilkens LA (2004) Electrosensory brain stem neurons compute the time derivative of electric fields in the paddlefish. Fluct Noise Lett 4:129–138CrossRefGoogle Scholar
  7. Hofmann MH, Chagnaud B, Wilkens LA (2005) Response properties of electrosensory afferent fibers and secondary brain stem neurons in the paddlefish. J Exp Biol 208:4213–4232PubMedCrossRefGoogle Scholar
  8. Hofmann MH, Wilkens LA (2005) Temporal analysis of moving dc electric fields in aquatic media. Phys Biol 2:23–28PubMedCrossRefGoogle Scholar
  9. Holt GR, Softky WR, Koch C, Douglas RJ (1996) Comparison of discharge variability in vitro and in vivo in cat visual cortex neurons. J Neurophysiol 75:1806–1814PubMedGoogle Scholar
  10. Knudsen E (1976) Midbrain units in catfish: response properties to electroreceptive input. J Comp Physiol 109:315–335CrossRefGoogle Scholar
  11. Kajikawa Y, Hackett TA (2005) Entropy analysis of neuronal spike train synchrony. J Neurosci Methods 149:90–93PubMedCrossRefGoogle Scholar
  12. McCreery DB (1977) Two types of electroreceptive lateral lemniscal neurons of the lateral line lobe of the catfishIctalurus nebulosus; connections from the lateral line nerve and steady-state frequency response characteristics. J Comp Physiol A 113:317–339CrossRefGoogle Scholar
  13. Nieuwenhuys R, ten Donkelaar HJ, Nicholson C (1998) The central nervous system of vertebrates. Springer, BerlinGoogle Scholar
  14. Peters RC, Evers HP (1985) Frequency selectivity in the ampullary system of an elasmobranch fish (Scyliorhinus canicula). J Exp Biol 118:99–109Google Scholar
  15. Peters RC, Evers HP, Vos J (1988) Tuning mismatch between peripheral and central sensory neurons reflects learning and adaptability. Adv Biosci 70:141–142Google Scholar
  16. Schweitzer J (1986) Functional organization of the electroreceptive midbrain in an elasmobranch (Platyrhinoidis triseriata). A single-unit study. J Comp Physiol A 158:43–58PubMedCrossRefGoogle Scholar
  17. Squire LR (2003) Fundamental neuroscience. Academic, AmsterdamGoogle Scholar
  18. Wilkens LA, Hofmann MH (2005) Behavior of animals with passive, low-frequency electrosensory systems. In: Bullock TH, Hopkins CD, Popper AN, Fay RR (eds) Electroreception. Springer, New York, pp 229–263CrossRefGoogle Scholar
  19. Wojtenek W, Hofmann MH, Wilkens LA (2001) Primary afferent electrosensory neurons represent paddlefish natural prey. Neurocomputing 38–40:451–458CrossRefGoogle Scholar
  20. Zupanc GKH, Bullock TH (2005) From electrogenesis to electroreception: an overview. In: Bullock TH, Hopkins CD, Popper AN, Fay RR (eds) Electroreception. Springer, New York, pp 5–46CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Boris P. Chagnaud
    • 1
  • Lon A. Wilkens
    • 1
  • Michael H. Hofmann
    • 1
  1. 1.Department of Biology, Center for NeurodynamicsUniversity of Missouri-St LouisSt LouisUSA

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