title: Resonant properties in the paddlefish electrosensory system caused by delayed feedback.
abstract: BACKGROUND
  The paddlefish electrosensory system consists of receptor cells in the skin that sense minute electric fields from their prey, small water fleas. The receptors thereby measure the difference of the voltage at the skin surface against the voltage inside the animal. Due to a high skin impedance, this internal voltage is considered to be relatively fixed.
  
  
  RESULTS
  We found, however, that this internal voltage can fluctuate. It shows damped oscillations to a single short electric field pulse and changes, with some time delay, according to the previous history of stimulation, and shows resonance at a certain frequency.
  
  
  CONCLUSIONS
  Computer simulations show that these phenomena can be explained by the presence of delayed feedback where the internal voltage is part of the feedback loop.
authors.affiliation: Center for Neurodynamics, Department of Biology, University of Missouri, St Louis, MO 63121, USA. hofmannm@umsl.edu
authors.forename: Michael H
authors.initials: MH
authors.lastname: Hofmann
authors.forename: S Nicola
authors.initials: SN
authors.lastname: Jung
authors.forename: Lon A
authors.initials: LA
authors.lastname: Wilkens
mesh_terms: D000818:Animals; D004555:Electric Fish / Q000502:physiology*; D004557:Electric Organ / Q000166:cytology / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D004574:Electromagnetic Fields; D005071:Evoked Potentials / Q000502:physiology; D005246:Feedback; D008959:Models, Neurological; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D011984:Sensory Receptor Cells / Q000502:physiology*; D013997:Time Factors