Potentials are recorded in the clinic using extracellular electrodes. These are near-field potentials as opposed to the far-field potentials recorded during studies of evoked potentials. Signals which approach, pass beneath an extracellular electrode and then continue onwards register a triphasic potential. Signals which do not pass beyond the electrode are characterised by a diphasic potential in which the initial positive wave is followed by a slow return to the baseline. Potentials which arise immediately beneath the recording electrode are diphasic, the initial phase being negative. These properties can be exploited to increase the size of recorded nerve action potentials.