Ensemble Characteristics of the Human Visual Evoked Response: Periodic and Random Stimulation

Most investigations of visual evoked potentials monitored at the human scalp have utilized the average of a series of responses recorded from a single subject in a specific population to define components of the visual evoked response (VER). While this technique provides a fairly consistent estimate of an individual's average VER, it is not uncommon to obtain quite dissimilar averages from different subjects under identical experimental conditions. This contrast in the VER estimates across a population has hindered the interpretation of the effects of stimulus parameters on the VER and frustrated the attempt to use this average for clinical diagnosis.