Functional relevance of cross-modal plasticity in blind humans
Functional relevance of cross-modal plasticity in blind humans
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DOI：
10.1038/38278
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发表时间：
1997-09-11
期刊：
影响因子：
64.8
通讯作者：
Hallett, M
中科院分区：
文献类型：
--
作者：
Cohen, LG;Celnik, P;Hallett, M
对自幼失明的人进行的功能成像研究表明，盲文阅读和其他触觉辨别任务可以激活他们的初级视觉皮质(1)。其他研究也表明，在盲人中，躯体感觉输入可以激活视觉皮质区域，但对有视力的人则不能。然而，这种跨模式可塑性的意义尚不清楚，因为尚不清楚视觉皮质是否能够以功能相关的方式处理体感信息。为了解决这个问题，我们使用经颅磁刺激来扰乱自幼失明的人在识别盲文或浮雕罗马字母时不同皮质区域的功能，对枕叶(视觉)皮质的瞬时刺激导致两项任务都有错误，并扭曲了盲人受试者的触觉感知，相比之下，枕部刺激对正常视力受试者的触觉表现没有影响，而类似的刺激已知会扰乱他们的视觉表现。我们的结论是，自幼失明会导致视觉皮质在躯体感觉处理中发挥作用。我们认为，这种跨通道可塑性可能部分解释了盲人受试者优越的触觉知觉能力。
Functional imaging studies of people who were blind from an early age have revealed that their primary visual cortex can be activated by Braille reading and other tactile discrimination task(1). Other studies have also shown that visual cortical areas can be activated by somatosensory input in blind subjects but not those with sight(2-7). The significance of this cross-modal plasticity is unclear, however, as it is not known whether the visual cortex can process somatosensory information in a functionally relevant way. To address this issue, we used transcranial magnetic stimulation to disrupt the function of different cortical areas in people who were blind from an early age as they identified Braille or embossed Roman letters, Transient stimulation of the occipital (visual) cortex induced errors in both tasks and distorted the tactile perceptions of blind subjects, In contrast, occipital stimu lation had no effect on tactile performance in normal-sighted subjects, whereas similar stimulation is known to disrupt their visual performance. We conclude that blindness from an early age can cause the visual cortex to be recruited to a role in somatosensory processing. We propose that this cross-modal plasticity may account in part for the superior tactile perceptual abilities of blind subjects.