Use of Dynamic-Clamp as a Tool to Reveal the Computational Properties of Single Neurons Embedded in Cortical Circuits

Dynamic clamp is a technique that combines computer modeling with experimental electrophysiology and is used to examine how specific ion channels modulate a variety of single-cell activities, by artificially emulating the response properties of specific ionic conductances during an electrophysiological recording. This is accomplished by continuously and instantaneously varying the current that is injected into a recorded neuron as a function of a computer-generated conductance and of the difference between its apparent reversal potential and the actual fluctuations of the membrane potential of the recorded cell. Dynamic clamp is often used to model voltage-independent, voltage-dependent, and synaptic ion currents and is very useful to study how cortical neurons compute and integrate diverse synaptic currents or sequences of synaptic inputs into specific spike-train outputs. Cortical networks are composed of highly heterogeneous cell types, and it is often difficult to dissect individual aspects of signal propagation between neurons and how they contribute to shape network activities underlying several cortical functions. Here, we describe some implementations of the dynamic clamp technique useful to studying the contribution of different elements of cortical circuits to the generation of single cell spike outputs.