Human Sensitivity to High Frequency Sine Wave and Pulsed Light Stimulation as Measured by the Steady State Cortical Evoked Response

摘要

The steady state cortical evoked response shows enhanced amplitude to a visual stimulus which is flickered in the frequency range between 38 Hz and 66 Hz. In this study, amplitude was found to be greatest at one particular frequency of stimulation, with the magnitude of the response to the peak frequency as much as double the amplitude of the surrounding frequencies. While all subjects demonstrated this enhancement, the particular frequency at which it was found varied from subject to subject. The range of peak frequencies was found to be 50 Hz to 56 Hz for the subjects studied. Sine wave modulated light produced this effect, while stroboscopic stimuli in the same frequency range did not produce it as clearly. It is hypothesized that this narrowly tuned response may be related to a subject's performance, as well as to other physiological characteristics of the individual. Since this amplitude increase is narrowly tuned, it is suggested that the advantages and disadvantages of stimulating humans at their peak frequency should be determined. Possible uses of this phenomena for studying brain functioning and behavior are discussed. (Author)