Generalized cable models of neurons and dendrites

Cable theory was introduced for neurons by Wilfrid Rall more than half a century ago, and is widely used today for modeling the voltage and current flow in neuronal and dendritic structures. This theory was derived assuming that the extracellular medium is either inexistent, or modeled as a resistor. For modeling neurons in more realistic situations, where the extracellular medium has more complex electric properties, it is necessary to generalize Rall’s cable equations. We summarize here such generalized cable equations, and show that the nature of the surrounding extracellular medium can exert non-negligible influences on the cable properties of neurons.