Assessment of cortical dysfunction in human strabismic amblyopia using magnetoencephalography (MEG)
Assessment of cortical dysfunction in human strabismic amblyopia using magnetoencephalography (MEG)
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DOI：
10.1016/s0042-6989(98)00259-4
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发表时间：
1999-05-01
期刊：
影响因子：
1.8
通讯作者：
Harding, GFA
中科院分区：
文献类型：
--
作者：
Anderson, SJ;Holliday, IE;Harding, GFA
本研究的目的是使用脑磁图(MEG)技术来确定斜视性弱视对人类枕叶皮质内空间信息处理的影响。我们使用基于19通道SQUID的神经磁强计记录了周期为0.5-4.0摄氏度(-1)的红色(红/绿)正弦色栅开始时的诱发磁反应。6个弱视者和6个正常视力的对照组被单眼记录到诱发反应，刺激被放置在每个观察者右下视野的中心凹附近。为了进行比较，使用两个交替的强迫选择心理物理程序测量了一个弱视者和一个对照的色栅检测的空间对比敏感度函数(CSF)。我们选择红/绿正弦波作为我们的刺激，是因为它们会从成年人的枕叶皮质(Fylan，Holliday，Singh，Anderson&Harding)引起强烈的磁反应。(1997年)。NeuroImage，6，47-57)。磁场强度被绘制为每个受试者每只眼睛的刺激空间频率的函数。只有弱视组的眼间差异明显：对于1-2摄氏度(-1)的刺激，弱视眼的诱发反应潜伏期显著延长，波幅显著降低(P<；0.05)。重要的是，缺陷的程度与斯内伦视力或对比敏感度无关。利用单等效电流偶极子模型对诱发反应进行定位。无论是正常受试者还是弱视受试者，震源定位与V1/V2交界处枕极的神经活动是一致的。我们的结论是，脑磁图对与人类弱视相关的皮质处理缺陷很敏感，可以用来进行定量的神经生理学测量。讨论了皮质缺陷的性质。(C)1999爱思唯尔科学有限公司。保留所有权利。
The aim of this study was to use the technique of magnetoencephalography (MEG) to determine the effects of strabismic amblyopia on the processing of spatial information within the occipital cortex of humans. We recorded evoked magnetic responses to the onset of a chromatic (red/green) sinusoidal grating of periodicity 0.5-4.0 c deg(-1) using a 19-channel SQUID-based neuromagnetometer. Evoked responses were recorded monocularly on six amblyopes and six normally-sighted controls, the stimuli being positioned near the fovea in the lower right visual field of each observer. For comparison, the spatial contrast sensitivity function (CSF) for the detection of chromatic gratings was measured for one amblyope and one control using a two alternate forced-choice psychophysical procedure. We chose red/green sinusoids as our stimuli because they evoke strong magnetic responses from the occipital cortex in adult humans (Fylan, Holliday, Singh, Anderson & Harding. (1997). Neuroimage, 6, 47-57). Magnetic field strength was plotted as a function of stimulus spatial frequency for each eye of each subject. Interocular differences were only evident within the amblyopic group: for stimuli of 1-2 c deg(-1), the evoked responses had significantly longer latencies and reduced amplitudes through the amblyopic eye (P < 0.05). Importantly, the extent of the deficit was uncorrelated with either Snellen acuity or contrast sensitivity. Localization of the evoked responses was performed using a single equivalent current dipole model. Source localizations, for both normal and amblyopic subjects, were consistent with neural activity at the occipital pole near the V1/V2 border. We conclude that MEG is sensitive to the deficit in cortical processing associated with human amblyopia, and can be used to make quantitative neurophysiological measurements. The nature of the cortical deficit is discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.