A microcomputer-controlled system for stimulation and acquisition of evoked potentials

A system, controlled by a microcomputer (LSI-11/23 with appropriate peripherals) for conducting evoked potential (EP) experiments, is described. In each experimental trial, a stimulus is applied and multichannel EEG is sampled, displayed, and stored in an output file. Any required length of pre- and poststimulus sampling periods is available. Stimuli are triggered by a human operator, aided by an on-line graphic display of sampled data. Automatic artifact monitoring is used for rejecting bad trials. Various stimulators may be used (simultaneously) and stimulus features (duration, power, number of pulses) may be changed in each trial. Lists of trial parameters, such as stimulus features and subject's response, are incorporated in the output file to facilitate cross-section analysis. The system was designed for the needs of pain EP research, but its flexibility and modularity make it useful in other areas of EP research.