A simple circuit for automatic continuous recording of microelectrode resistance

Publisher Website
Google Scholar
Abstract
Microelectrodes with tip diameters ≤0.5 μm used for intracellular recording sometimes give artefactual readings due to tip potentials. These appear to be caused by a change in the tip of the microelectrode upon impalement with a corresponding change in microelectrode resistance. A circuit is described which enables the resistance of the microelectrode to be continuously monitored throughout an experiment. The electrode is used as one half of a potential divider for an a.c. signal at 20 Hz with an amplitude of 20 mV. The other half of the potential divider is a 1000 mΩ resistor. The a.c. signal across the microelectrode is approximately proportional to the microelectrode resistance in the range 0–50 MΩ. This signal is amplified, rectified and smoothed and then displayed on a chart recorder or other convenient meter.

This publication has 6 references indexed in Scilit: