Program in Cognitive Neuroscience, Department of Psychology, City College of the City University of New York, New York, NY 10031, USA.
Exp Brain Res. 2012 Jul;220(2):191-9. doi: 10.1007/s00221-012-3129-1. Epub 2012 May 29.
The VESPA (visual-evoked spread spectrum analysis) method estimates the impulse response of the visual system using a continuously varying stimulus. It has been used recently to address both basic cognitive and neurophysiologic questions as well as those surrounding clinical populations. Although the components of the average VESPA response are highly reminiscent of the early components of the visual-evoked potential (VEP) when measured over midline occipital locations, the two responses are acquired in different ways and, thus, they cannot be regarded as being equivalent. To further characterize the relationship between the VESPA and the VEP and the generative mechanisms underlying them, we recorded EEG from 31 subjects in response to checkerboard-based VEP and VESPA stimuli. We found that, across subjects, the amplitudes of the VEP C1 component and the VESPA C1 component were highly correlated, whereas the VEP P1 and the VESPA P1 bore no statistical relationship. Furthermore, we found that C1 and P1 amplitudes were significantly correlated in the VESPA but not in the VEP. We believe these findings point to the presence of common generators underlying the VESPA C1 and the VEP C1. We argue further that the VESPA P1, in light of its strong relationship to the VESPA C1, likely reflects further activation of the same cortical generators. Given the lack of correlation between the VEP P1 and each of these three other components, it is likely that the underlying generators of this particular component are more varied and widespread, as suggested previously. We discuss the implications of these relationships for basic and clinical research using the VESPA and for the assessment of additive-evoked versus phase-reset contributions to the VEP.
VESPA（视觉诱发扩频分析）方法使用连续变化的刺激来估计视觉系统的脉冲响应。它最近已被用于解决基础认知和神经生理问题以及临床人群问题。尽管从中线枕部位置测量时，平均 VESPA 响应的成分非常类似于视觉诱发电位（VEP）的早期成分，但这两种响应是通过不同的方式获得的，因此不能认为它们是等效的。为了进一步描述 VESPA 与 VEP 之间的关系以及它们的产生机制，我们记录了 31 名受试者对基于棋盘的 VEP 和 VESPA 刺激的脑电图。我们发现，在受试者之间，VEP 的 C1 成分和 VESPA 的 C1 成分的幅度高度相关，而 VEP 的 P1 和 VESPA 的 P1 没有统计学关系。此外，我们发现 C1 和 P1 幅度在 VESPA 中显著相关，但在 VEP 中则没有。我们认为这些发现表明 VESPA C1 和 VEP C1 具有共同的发生器。我们进一步认为，鉴于 VESPA P1 与 VESPA C1 之间的强关系，它可能反映了相同皮质发生器的进一步激活。鉴于 VEP P1 与这三个其他成分中的每一个都没有相关性，因此，很可能这个特定成分的潜在发生器更加多样化和广泛，如前所述。我们讨论了这些关系对使用 VESPA 进行基础和临床研究以及评估附加诱发与相位重置对 VEP 的贡献的意义。
