AbstractElectrical signalling in the brain connects over 10^10 neurons. Thin unmyelinated axons are important as the grey substance in the cortex depend on these. Because they are so thin, however, they have been difficult to study with traditional intracellular recording techniques. A lot of knowledge about thin unmyelinated axons is derived from the studies of larger axons, but the differences in morphology, and therefore probably also function, is significant. This will certainly affect propagation of the action potential through the axon. In this student project I will look at how a neuron is modelled with topological and biophysical properties. I will introduce some mathematics used in electrophysiology. That is mathematics mainly from cable theory and the Hodgkin and Huxley equations. With this background I will build a simple neuron with a long, thin axon for a simulation of action potentials. This is done with a multi-compartmental model. Simulations in computer programs like NEURON can give new insights and also redirect research on real neurons. The simulations can also help interpret results from some new measurement techniques of real neurons such as the measurement of a terminal 'bleb' made in response to the slicing procedure of the axon. The overall aim is to improve the knowledge we have of the nervous system.