Electroencephalographic evidence of sensory gating in the occipital visual cortex.

Sensory gating refers to the suppression of the neuronal response to a repeating stimulus and is considered a protection mechanism in the brain. In this study, we assessed gating of the mid-latency components of the visual evoked potentials (N75, P100, N150) in 11 healthy individuals using a paired-flash paradigm. A significant decrease of P100 and N150 amplitudes was shown; additionally, a significant increase in the latency of N75 and P100 for the second stimulus of the pair compared with the first one was also observed. Absolute power of the stimulus 2 signal at theta frequency was significantly suppressed as compared with the stimulus 1 signal. These results indicate a gating effect in the visual modality, reflected in both time-domain and frequency-domain measures.