Spatial frequency-specific potentiation of human visual-evoked potentials.
Recent research has suggested that cortical long-term potentiation can be induced non-invasively in humans by using rapid visual stimulation. The present study extends these findings by investigating the specificity of this long-term potentiation effect to the inducing stimulus. One group of study participants were tetanized using a one cycle-per-degree sine grating, while a second group was tetanized using a five cycles-per-degree sine grating. Using electroencephalography, we found that an increase in the N1b potential was specific to sine gratings of the same frequency as the tetanus. No effect was observed in the N1b for sine gratings of a different spatial frequency. These results suggest that the long-term potentiation effect induced by the sensory tetanus is isolated to a discrete neural population in the visual cortex.