Different activation patterns in the visual cortex of late and congenitally blind subjects
Different activation patterns in the visual cortex of late and congenitally blind subjects
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DOI：
10.1093/brain/121.3.409
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发表时间：
1998-03-01
期刊：
影响因子：
14.5
通讯作者：
Friston, K
中科院分区：
文献类型：
--
作者：
Büchel, C;Price, C;Friston, K
发育神经科学中的一个关键问题是视皮层功能组织的表观遗传诱导中活动依赖机制的作用。眼盲和随后的视觉剥夺是一个罕见的模型，可用于调查的经验依赖性皮层重组man.In PET研究中，我们表明，先天性失明的受试者显示任务特定激活的纹外视觉区和顶叶联合区在盲文阅读，与听觉文字处理。相比之下，青春期后失明的盲人在完成同样的任务时，初级视觉皮层表现出额外的激活。对蒙眼饲养的猴子的研究表明，躯体感觉刺激可以引起纹外区的跨模态反应。这与我们先天失明受试者触觉处理引起的跨模态纹外激活一致。由于初级视觉皮层也不显示在灵长类动物的研究中的跨模态反应，在后期和先天性失明的受试者的差异激活突出的可能性，相互激活的视觉意象在受试者的早期视觉经验。
A key issue in developmental neuroscience is the role of activity-dependent mechanisms in the epigenetic induction of functional organization in visual cortex. Ocular blindness and ensuing visual deprivation is one of the rare models available for the investigation of experience-dependent cortical reorganization in man. In a PET study we demonstrate that congenitally blind subjects show task-specific activation of extrastriate visual areas and parietal association areas during Braille reading, compared with auditory word processing. In contrast, blind subjects who lost their sight after puberty show additional activation in the primary visual cortex with the same tasks. Studies in blind-raised monkeys show that crossmodal responses in extrastriate areas can be elicited by somatosensory stimulation. This is consistent with the crossmodal extrastriate activations elicited by tactile processing in our congenitally blind subjects. Since primary visual cortex does nor show crossmodal responses in primate studies, the differential activation in late and congenitally blind subjects highlights the possibility of reciprocal activation by visual imagery in subjects with early visual experience.