Measurement of cell impedance in frequency domain using discontinuous current clamp and white-noise-modulated current injection.
A method is described for the determination of cellular input impedance of non-spiking neurones. The input impedance is important when cellular geometry and the effects of voltage-dependent channels are considered. Cells are impaled with a single glass microelectrod and current is injected using a time-sharing technique. The cell's impedance is measured by randomly modulating the injected current and calculating the impedance as a transfer function between current and recorded membrane voltage. Corresponding coherence functions can also be calculated for estimating the signal-to-noise ratio, and also linearity (i.e. possible activation of voltage-dependent conductances) of the membrane.
D000818:Animals; D003058:Cockroaches / Q000502:physiology*; D017097:Electric Impedance; D004566:Electrodes; D007473:Ion Channels / Q000378:metabolism; D008839:Microelectrodes; D009474:Neurons / Q000502:physiology*; D010786:Photoreceptor Cells / Q000502:physiology; D015221:Potassium Channels / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology
D007473:Ion Channels; D015221:Potassium Channels