Influence of the electrode configuration on the results of electrophysiological studies

The problem that initiated this study was that the authors encountered a situation that similar electrophysiological experimental studies, performed (by various researchers) using different measurement techniques, often produced non-compatible results. Analysis of the possible causes of the discrepancies indicated that the use of various electrode configurations may be a significant contributing factor. The purpose of this work was to theoretically analyze the response profiles of various types, sizes and geometries of electrode systems when attached to a typical muscular tissue. The authors analyzed needle electrodes, simulating various tissue fiber vs. electrode axis orientations, as well as various tissue size/thickness/inter-electrode separation ratios. They also performed studies for various surface-spot electrode systems. Simulations showed that needle electrodes may have quite different response profiles compared to surface-spot electrodes. Also, the sample size/thickness/inter-electrode separation ratio significantly influences the response profiles. The authors´ conclusion is that, for “macroscopic” electrophysiological studies (at tissue levels), it is a fundamental requirement to custom design the electrode system for each experiment, if optimal and reproducible results are expected