fMRI with Central Vision Loss: Effects of Fixation Locus and Stimulus Type.
fMRI with Central Vision Loss: Effects of Fixation Locus and Stimulus Type.
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中心视力丧失的功能磁共振成像：注视点和刺激类型的影响
DOI：
10.1097/opx.0000000000001047
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Greenlee
中科院分区：
文献类型：
--
作者：
Brandl-Rühle;Renner;Jägle;Greenlee
目的：在中央视野黑斑患者中，大部分视皮层未得到充分刺激。患者通常在完整的周围视网膜上使用一个新的偏心固定区域（“首选视网膜轨迹”-PRL），其功能相当于伪中央凹。我们使用功能性磁共振成像（fMRI）来检查刺激伪中央凹是否会导致视觉皮层的激活增加或激活模式改变，而不是刺激对侧半球的类似外周区域（OppPRL）。方法对19例遗传性视网膜营养不良所致双目中央暗斑患者和年龄相匹配的对照组进行观察。在fMRI测量过程中，用闪烁的棋盘刺激和物体图像刺激视野中心、PRL和OppPRL。结果显示，与闪烁的棋盘刺激相比，日常物品图片刺激导致视觉皮层总体上更大的BOLD（血氧水平依赖）反应。患者早在V1期就表现出这种增强。当物体图像直接刺激PRL时，早期视觉皮层的中央表征区在患者中被共同激活，而在对照组中没有。在视网膜异位皮层以外的高级视觉区域，与刺激OppPRL区域相比，用物体图像刺激PRL的BOLD反应显着增强。PRL高度稳定的偏心固定与患者视觉皮层中较高的BOLD信号相关，这种影响在物体图像刺激的情况下最为明显。结论中枢性视力丧失患者早期视觉皮层中，自然图像更容易触发自上而下的调节激活过程。
PurposeIn patients with central visual field scotomata, a large part of visual cortex is not adequately stimulated. Patients often use a new eccentric fixation area on intact peripheral retina (“preferred retinal locus”—PRL) that functions as a pseudo-fovea. We used functional magnetic resonance imaging (fMRI) to examine whether stimulating this pseudo-fovea leads to increased activation or altered activation patterns in visual cortex in comparison to stimulating a comparable peripheral area in the opposite hemifield (OppPRL).MethodsNineteen patients with binocular central scotomata caused by hereditary retinal dystrophies and an age-matched control group were tested. The center of the visual field, PRL, and OppPRL were stimulated with flickering checkerboard stimuli and object pictures during fMRI measurement.ResultsResults show that stimulation with pictures of everyday objects led to overall larger BOLD (blood oxygen level dependent) responses in visual cortex compared to that evoked by stimulation with flickering checkerboards. Patients showed this enhancement as early as in V1. When the PRL was directly stimulated with object pictures, the central representation area in early visual cortex was coactivated in the patients but not in the controls. In higher visual areas beyond retinotopic cortex, BOLD responses to stimulation of the PRL with object pictures were significantly enhanced in comparison to stimulation of the OppPRL area. Highly stable eccentric fixation with the PRL was associated with a higher BOLD signal in visual cortex in patients, and this effect was most pronounced in the conditions with object picture stimulation.ConclusionsThe observed results suggest that naturalistic images are more likely to trigger top-down processes that regulate activation in early visual cortex in patients with central vision loss.
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影响因子：
4.4
作者：
Stephen G. Whirraker;James Dudd;ond Roger W. Cummings
通讯作者：
Stephen G. Whirraker;James Dudd;ond Roger W. Cummings
影响因子：
64.8
作者：
AZZOPARDI, P;COWEY, A
通讯作者：
COWEY, A
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影响因子：
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作者：
Farzana;Brandl-Rühle;Renner;Greenlee
通讯作者：
Greenlee
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DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
H. Baseler;A. Gouws;A. Morland
通讯作者：
A. Morland
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影响因子：
1.4
作者：
L. Scullica;B. Falsini
通讯作者：
B. Falsini