Review of signal distortion through metal microelectrode recording circuits and filters

J Neurosci Methods. 2008 Mar 30;169(1):141-57. doi: 10.1016/j.jneumeth.2007.12.010. Epub 2008 Feb 1.


Interest in local field potentials (LFPs) and action potential shape has increased markedly. The present work describes distortions of these signals that occur for two reasons. First, the microelectrode recording circuit operates as a voltage divider producing frequency-dependent attenuation and phase shifts when electrode impedance is not negligible relative to amplifier input impedance. Because of the much higher electrode impedance at low frequencies, this occurred over frequency ranges of LFPs measured by neurophysiologists for one head-stage tested. Second, frequency-dependent phase shifts are induced by subsequent filters. Thus, we report these effects and the resulting amplitude envelope delays and distortion of waveforms recorded through a commercial data acquisition system and a range of tungsten microelectrodes. These distortions can be corrected, but must be accounted for when interpreting field potential and spike shape data.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Action Potentials / physiology*
  • Animals
  • Artifacts*
  • Brain / physiology
  • Electric Impedance
  • Electronics / instrumentation*
  • Electronics / methods
  • Electrophysiology / instrumentation*
  • Electrophysiology / methods
  • Microelectrodes / standards
  • Neurons / physiology
  • Neurophysiology / instrumentation*
  • Neurophysiology / methods
  • Signal Processing, Computer-Assisted / instrumentation*