Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China 200031.
J Physiol. 2011 Jul 1;589(Pt 13):3125-33. doi: 10.1113/jphysiol.2011.205245. Epub 2011 May 3.
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.
周期性感觉刺激在自然环境中很常见，可能是特定事件的信号。然而，神经回路是否对周期性和非周期性刺激进行差异化处理尚不清楚。本文表明，在神经元和感知水平上，周期性刺激的影响范围大于非周期性刺激。对大鼠视觉皮层的全细胞膜片钳记录显示，神经元感受野外的周期性视觉刺激（1-11 Hz）会在刺激频率下引起强烈的膜电位振荡，而以非周期性方式施加相同的刺激则几乎没有影响。人类心理物理学实验表明，远距离周围的周期性亮度变化也比非周期性变化对中心测试刺激的感知亮度产生更强的调制。此外，周期性周围刺激的刺激循环次数增加，会引起感知和神经元的调制都增加。因此，周期性刺激可以在更大的空间尺度上调节皮质反应和视觉感知，对皮质信息处理产生更广泛的影响。
