加拿大蒙特利尔大学科学家发现，大脑具有惊人的可塑性，正常情况下与眼睛相连的视觉信息处理与空间感知脑区，也能与声音信息形成重新连接，因此一些先天性失明的盲人能通过声音来感知空间，实现以耳代目。该研究发表在3月15日的美国《国家科学院院刊》（PNAS）上。
蒙特利尔大学圣-贾斯汀医学研究中心奥利弗·柯利根和神经心理学与认知研究中心的弗朗哥·莱普合作，对11位先天失明者和11位正常人进行了比较研究。研究人员在给他们听不同声音的同时，用核磁共振成像（MRI）扫描他们的脑部活动。此前的一些研究也显示，盲人在将声音处理作为空间感知方面的能力比正常人要强。柯利根解释说：“之前的研究表明，先天失明的人脑部枕区与非视觉信息处理过程有关。而我们最近的研究表明，盲人的脑部枕区在与声音信息处理系统重新连接之后，其视觉皮层还保留着像正常人那样的功能组织。视觉皮层中右背侧枕流区的某些地方能将原有大脑神经网络的功能重新组合，以处理空间信息。”视觉皮层位于大脑后部，左右半球各有一个，称为枕叶，负责处理视觉画面。
柯利根认为，这证明大脑具有惊人的可塑性，而可塑性是指大脑由于阅历经验变化而发生变化的能力。大脑中有专门的脑区用于空间处理，即使一个人刚出生就失明，他的大脑也非常灵活，可以让神经元周围的微环境发展变化，使神经元拥有并执行一些新功能。
对于先天失明婴儿的大脑如何发育出这种重新连接，柯利根解释说，在早期生命中，大脑在经验感受的基础上塑造着自身，某些突触连接消失了，而另一些会得到加强，突触连接使神经元得以互相交流。“在婴儿8个月左右，大脑发育高峰结束，此后大约40%的视觉皮层突触开始逐渐移除，到11岁左右突触密度达到稳定。重新连接的发生，可能是作为不断变化的神经连接维护机制的一部分，但这一理论还需要进一步检验。”（生物谷Bioon.com）
生物谷推荐原文出处：
PNAS doi: 10.1073/pnas.1013928108
Functional specialization for auditory–spatial processing in the occipital cortex of congenitally blind humans
Olivier Collignona,b,1, Gilles Vandewallec, Patrice Vossa, Geneviève Albouyc, Geneviève Charbonneaua, Maryse Lassondea,b, and Franco Leporea
Abstract
The study of the congenitally blind (CB) represents a unique opportunity to explore experience-dependant plasticity in a sensory region deprived of its natural inputs since birth. Although several studies have shown occipital regions of CB to be involved in nonvisual processing, whether the functional organization of the visual cortex observed in sighted individuals (SI) is maintained in the rewired occipital regions of the blind has only been recently investigated. In the present functional MRI study, we compared the brain activity of CB and SI processing either the spatial or the pitch properties of sounds carrying information in both domains (i.e., the same sounds were used in both tasks), using an adaptive procedure specifically designed to adjust for performance level. In addition to showing a substantial recruitment of the occipital cortex for sound processing in CB, we also demonstrate that auditory–spatial processing mainly recruits the right cuneus and the right middle occipital gyrus, two regions of the dorsal occipital stream known to be involved in visuospatial/motion processing in SI. Moreover, functional connectivity analyses revealed that these reorganized occipital regions are part of an extensive brain network including regions known to underlie audiovisual spatial abilities (i.e., intraparietal sulcus, superior frontal gyrus). We conclude that some regions of the right dorsal occipital stream do not require visual experience to develop a specialization for the processing of spatial information and to be functionally integrated in a preexisting brain network dedicated to this ability.
