School of Psychology, University of Western Australia, Australia.
Cephalalgia. 2012 Jan;32(2):125-39. doi: 10.1177/0333102411432725. Epub 2011 Dec 15.
Increased contrast-level dependent internal noise has been reported in migraine. This study aimed to investigate whether a general increase in internal noise impacted on other tasks thought to assess functioning in cortical area V1 and was evident in global contour coding (V4).
Eleven migraineurs (six with aura) and 12 headache-free controls completed three psychophysical tasks: (i) contrast detection, (ii) discrimination of the angle of a spiral path and (iii) detection of deformation from circularity. Internal noise estimates were obtained using an N-pass method that compared responses to repeated presentations of identical stimuli. Internal noise results in inconsistent responses across different runs.
Migraineurs had significantly higher contrast thresholds when there was high external luminance noise. There were no other significant group differences in thresholds. Increased multiplicative noise associated with contrast processing was replicated and increased additive noise, which is independent of the visual input, was found for the global form task.
This study provides further evidence for increased multiplicative internal noise associated with contrast processing in migraineurs. However there is no generalised increase in internal noise in V1 as noise estimates for angular discrimination were normal. Increased additive internal noise was associated with the global shape task, co-occurring with increased efficiency.
偏头痛患者的对比度依赖内部噪声增加。本研究旨在探讨内部噪声的普遍增加是否会影响到其他被认为评估 V1 皮质区功能的任务，并且这种影响在全局轮廓编码（V4）中是否明显。
11 名偏头痛患者（6 名伴先兆）和 12 名无头痛对照者完成了三项心理物理任务：（i）对比度检测，（ii）螺旋路径角度辨别，（iii）圆形变形检测。使用 N 次通过方法获得内部噪声估计值，该方法比较了对相同刺激重复呈现的反应。内部噪声会导致不同运行之间的响应不一致。
偏头痛患者在高外部亮度噪声时对比度阈值显著升高。在阈值方面，两组之间没有其他显著差异。对比度处理相关的乘法噪声增加得到了复制，并且在全局形状任务中发现了与视觉输入无关的加法噪声增加。
本研究进一步提供了偏头痛患者对比度处理相关的内部噪声增加的证据。然而，在 V1 中没有普遍的内部噪声增加，因为角度辨别噪声估计值正常。与效率增加相关的全局形状任务，与增加的加法内部噪声有关。
