Action Potential Propagation along Myelinated Axons
Action Potential Propagation along Myelinated Axons
An action potential travels down the myelinated axon of a neuron. In between myelin sheath sections (indicated by light blue boxes) at the nodes of Ranvier (indicated by vertical red lines in the plot), the potential is modeled by Hodgkin–Huxley dynamics. The propagation of the signal along the myelinated sections is described by the linear cable equation, whose space and time constants are variable, as well as by the inter-node distance. The signal is initiated at the left-end node by an external current pulse or constant step of adjustable magnitude. The time course of a single point along the axon is displayed in the top right. You can see the speed of signal propagation in real time using the autoplay feature of the time slider.