The effect of residual electrode resistance and sampling delay on transient instability in the dynamic clamp system

The dynamic clamp technique uses feedback to combine computational modeling with electrophysiology experiments. It is commonly used to simulate computational ionic currents in real-time and inject the resulting current into the neuron, as if it were part of the cell. Increasing the magnitude of the simulated conductances leads to transient instabilities. In this paper we use physical experiments, computational simulation, and stability analysis to examine the effects uncompensated electrode resistance and sampling delay have on this transient instability. We find that uncompensated electrode resistance decreases the maximum usable conductance that maintains a stable system. Also, we find that commonly used sampling rates limit the maximum conductance that maintains a stable system, and that these limitations are not due to the kinetics of the underlying ion channel model.