Training-induced cortical representation of a hemianopic hemifield
Training-induced cortical representation of a hemianopic hemifield
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DOI：
10.1136/jnnp.2006.099374
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发表时间：
2007-01-01
影响因子：
11
通讯作者：
Vanni, S.
中科院分区：
文献类型：
--
作者：
Henriksson, L.;Raninen, A.;Vanni, S.
背景：同向偏盲患者在盲侧视野中对视觉刺激常存在一定的残余敏感度。以往的影像学研究表明，纹外皮质区在这种残余视力中起着重要作用，但训练改善偏盲患者视力的结果是相互矛盾的。目的：显示在中风慢性期使用闪烁刺激的强化训练可以重组成年患者的视皮质。一位61岁的同侧偏盲患者在中风后22个月开始接受闪烁刺激训练。在训练过程中的功能变化记录与脑磁图，和训练后的皮层组织进行了检查与功能磁共振成像（fMRI）。结果：这两种成像方法表明，训练后，视觉信息从两个hemifields主要是在完整的半球处理。功能磁共振成像成像结果显示，盲人和正常人的半野在完整半球的同一组皮质区中，更具体地说，在视觉运动敏感区V5、上级颞沟周围区域和视网膜视区V1中，都有代表性（初级视皮层）、V2、V3和V3a。盲半野的强化训练可以诱导成年患者的皮质重组，这个病例显示了训练后的视觉半野在包括初级视觉皮层在内的几个皮层区域的同侧表现。
Background: Patients with homonymous hemianopia often have some residual sensitivity for visual stimuli in their blind hemifield. Previous imaging studies suggest an important role for extrastriate cortical areas in such residual vision, but results of training to improve vision in patients with hemianopia are conflicting.Objective: To show that intensive training with flicker stimulation in the chronic stage of stroke can reorganise visual cortices of an adult patient.Methods: A 61-year-old patient with homonymous hemianopia was trained with flicker stimulation, starting 22 months after stroke. Changes in functioning during training were documented with magnetoencephalography, and the cortical organisation after training was examined with functional magnetic resonance imaging (fMRI).Results: Both imaging methods showed that, after training, visual information from both hemifields was processed mainly in the intact hemisphere. The fMRI mapping results showed the representations of both the blind and the normal hemifield in the same set of cortical areas in the intact hemisphere, more specifically in the visual motion-sensitive area V5, in a region around the superior temporal sulcus and in retinotopic visual areas V1 (primary visual cortex), V2, V3 and V3a.Conclusions: Intensive training of a blind hemifield can induce cortical reorganisation in an adult patient, and this case shows an ipsilateral representation of the trained visual hemifield in several cortical areas, including the primary visual cortex.