[Effect of the spatial frequency of sinusoidal gratings on amplitude and temporal parameters of visual evoked...

Visual evoked potentials (EPs) in response to sinusoidal gratings of different contrast, with spatial frequencies of 0,5-15 cycles/grad presented in "on-off" order, were studied in six grown-up subjects with normal sight. Peak latencies of all EP components and the amplitude of the relatively early N95-130-P-120-190 complex increased with increasing spatial frequency. Presentation of low-frequency gratings led to an increase of the late EP complex (N150-230-P 210-290). The EP configuration in response to sinusoidal gratings of different spatial frequencies determined by the dominance of the early or late EP complex is supposed to reflect involvement of independent mechanisms of processing of information on low or high spatial frequency differently localized in the visual cortex.