Computerised topographical mapping of scalp recorded event-related potentials

A technique is described for the recording of multichannel cerebral evoked potential data and their conversion to colour-coded displays of scalp electrical activity at up to 40 instants in time. Such mapping gives a more readily assimilated picture of the evolution of the potential changes over the scalp than the raw waveforms. The method employs a PDP 11/23 computer for data collection and surface topography calculation, and a Tektronix 4662 digital plotter with 8 colour option for the display of spatio-temporal maps.