Visual evoked potentials and reaction times: influence of stimulus parameters

Manual reaction time measurements were used to investigate the transmission characteristics of the visual channel by analyzing the input-output relationship for different stimuli. A stimulus-dependent influence is neglected by the assumption of a constant delay time of the motor system. In order to check this approach, visual evoked EEG potentials were measured, and their latencies were compared to the reaction time data. Good agreement between measures was shown only on the basis of the mean values. On the single-trial level, no systematic correlation could be found. Methodological problems of processing single-trial visual evoked potentials are discussed, and the results are interpreted with respect to models of the sensory-motor system.<>