ELECTRICAL AND BIOLOGICAL PROPERTIES OF TUNGSTEN MICROELECTRODES

Electrical measurements have been made on varnish insulated tungsten microelectrodes in an attempt to obtain a guide to their suitability for recording from nerve cells in the central nervous system. The variability of the behaviour of the metal-electrolyte interface rules out most tests. The series resistance offered by the electrolyte can be reliably estimated and, since it depends only upon the apparent size and shape of the free tip and upon the electrolyte resistivity, may be taken as an overall assessment of tip geometry. A correlation is demonstrated between the value of the series electrolyte resistance and the performance in detecting activity in the cerebral cortex. © 1968 International Federation for Medical and Biological Engineering.