Periodic stimulation induces long-range modulation of cortical responses and visual perception.

Periodic sensory stimuli are prevalent in natural environment and may signal events of particular importance. However, whether periodic and aperiodic stimuli are differentially processed by neural circuits remains unclear. Here we show that periodic stimuli exert influences over longer distances than aperiodic stimuli at both neuronal and perceptual levels. Whole-cell recording from rat visual cortex showed that periodic visual stimulation (1-11 Hz) outside the neuronal receptive field evoked robust membrane potential oscillation at the stimulation frequency, while the same stimulus applied aperiodically had little effect. Human psychophysical experiments showed that periodic luminance changes in the distant surround also exert a stronger modulation of perceived brightness of a centre test stimulus than that exerted by aperiodic changes. Furthermore, both perceptual and neuronal modulation increased with the number of stimulation cycles for periodic surround stimuli. Thus, periodic stimuli can modulate both cortical responses and visual perception over larger spatial scales, generating more global impact on cortical information processing.