Trimble J L, Potts A M
Invest Ophthalmol. 1975 Jul;14(7):537-46.
As a first step toward determining the source of variability in the visually evoked response (VER) between subjects, we have examined the relationships between the VER and the alpha-rhythm. This was done by comparing the VER's to photic stimuli delivered at positive and negative peaks of the alpha-rhythm (alpha-synchronized stimuli) with VER's to flashes delivered at a fixed interval, unsynchronized with the alpha-rhythm. Average VER's for the three classes of stimuli were calcuated for each of ten subjects. In addition, a grand average VER (GVVER) WAS CALCULATED FOR EACH STIMULUS CLASS BY AVERAGING THE INDIVIDUAL AVERAGE VER's. Quantitative comparisons between GVER's were made using cross- correlograms. Cross-correlograms were calculated between each of the GVER's, and between the GVER's to alpha-synchronized stimulation and their controls. These data show that the first 120 msec. poststimulus interval of the Gver's to alpha-synchronized stimulation are highly correlated with the prestimulus alpha- rhythm. The data also show a component occurring in al GVER's which is independent of the alpha-rhythm. This component begins 120 msec. After stimulation, reaches peak amplitude at 200 msec, and decays to baseline at 240 msec. Thses findings suggest that much of the variability in VER recordings may be due to alpha-activity which has been insufficiently attenuated by averaging.
作为确定个体间视觉诱发电位（VER）变异性来源的第一步，我们研究了VER与α波节律之间的关系。通过比较在α波节律的正峰和负峰处给予光刺激（α同步刺激）时的VER与以固定间隔给予、与α波节律不同步的闪光刺激时的VER来实现这一点。为十名受试者中的每一位计算了这三类刺激的平均VER。此外，通过对个体平均VER进行平均，为每类刺激计算了一个总体平均VER（GVVER）。使用互相关图对GVVER进行定量比较。计算了每个GVVER之间以及α同步刺激的GVVER与其对照之间的互相关图。这些数据表明，α同步刺激的GVVER在刺激后120毫秒内的间隔与刺激前的α波节律高度相关。数据还显示，在所有GVVER中都出现了一个与α波节律无关的成分。该成分在刺激后120毫秒开始，在200毫秒达到峰值幅度，并在240毫秒衰减至基线。这些发现表明，VER记录中的许多变异性可能是由于平均处理未能充分衰减的α活动所致。
