Department of Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.
Invest Ophthalmol Vis Sci. 2013 Feb 1;54(2):1160-8. doi: 10.1167/iovs.12-11242.
Individuals with migraine show subtle defects in a range of visual tasks compared to nonmigraineurs. Increased neuronal noise can account for some of these deficits. To examine the generality of increased noise in migraine, masking effects were compared in migraineurs and headache-free controls using a shape discrimination task, thought to involve processing in extrastriate cortical areas.
Nine migraineurs with aura, nine migraineurs without aura, and nine headache-free controls participated. observers had to detect deviations in circular shapes with or without a larger contour mask. The nonoverlapping mask was presented at five temporal intervals (stimulus onset asynchronies, SOA): 0 (simultaneous), 66, 100, 133, and 250 ms.
Migraineurs with aura performed worse in all tests than migraineurs without aura and controls. Both migraine groups performed poorer than controls at discriminating shapes without masks. Typical masking functions were obtained from all groups, but they were steeper for migraineurs than controls with thresholds raised most dramatically (2.1 and 4.4 times for migraineurs without and with aura relative to controls, respectively) at SOAs where masks had their most detrimental effect (66-100 ms). Modeling the effect of masking showed that raised internal noise alone is insufficient to explain these deficits. Rather, an abnormal nonlinear transducer function (e.g., as part of gain-control) together with increased multiplicative noise is required to capture the data.
The findings are consistent with an extrastriate deficit in migraine that cannot be explained completely by defective inhibition.
与非偏头痛患者相比，偏头痛患者在一系列视觉任务中存在细微缺陷。神经元噪声增加可以解释其中的一些缺陷。为了研究偏头痛中噪声增加的普遍性，使用形状辨别任务比较了偏头痛患者和无头痛对照组之间的掩蔽效应，该任务被认为涉及到纹外皮质区域的处理。
9 名有先兆偏头痛患者、9 名无先兆偏头痛患者和 9 名无头痛对照组参与了研究。观察者必须在有或没有较大轮廓掩蔽的情况下检测圆形形状的偏差。非重叠掩蔽在五个时间间隔（刺激起始异步，SOA）呈现：0（同时）、66、100、133 和 250ms。
有先兆偏头痛患者在所有测试中表现均差于无先兆偏头痛患者和对照组。两组偏头痛患者在无掩蔽的情况下辨别形状的表现均差于对照组。所有组均获得了典型的掩蔽函数，但偏头痛患者的函数斜率大于对照组，阈值在掩蔽效果最明显的 SOA（66-100ms）处升高最为显著（无先兆和有先兆偏头痛患者相对于对照组分别升高了 2.1 和 4.4 倍）。对掩蔽效应进行建模表明，仅增加内部噪声不足以解释这些缺陷。相反，需要异常的非线性换能器功能（例如，作为增益控制的一部分）以及增加的乘法噪声来捕获数据。
这些发现与偏头痛中的纹外缺陷一致，这种缺陷不能完全用抑制缺陷来解释。
