Fischer-Baum Simon, Jang Ava, Kajander David
Department of Psychology, Rice University, Houston, TX, USA.
Department of Psychology, University of Massachusetts, Amherst, MA, USA.
Neural Plast. 2017;2017:2761913. doi: 10.1155/2017/2761913. Epub 2017 Feb 8.
Damage to certain left hemisphere regions leads to reading impairments, at least acutely, though some individuals eventually recover reading. Previous neuroimaging studies have shown a relationship between reading recovery and increases in contralesional and perilesional activation during word reading tasks, relative to controls. Questions remain about how to interpret these changes in activation. Do these changes reflect functional take-over, a reorganization of functions in the damaged brain? Or do they reveal compensatory masquerade or the use of alternative neural pathways to reading that are available in both patients and controls? We address these questions by studying a single individual, CH, who has made a partial recovery of reading familiar words following stroke. We use an fMRI analysis technique, representational similarity analysis (RSA), which allows us to decode cognitive function from distributed patterns of neural activity. Relative to controls, we find that CH shows a shift from visual to orthographic processing in contralesional regions, with a marginally significant result in perilesional regions as well. This pattern supports a contralesional reorganization of orthographic processing following stroke. More generally, these analyses demonstrate how powerful RSA can be for mapping the neural plasticity of language function.
某些左半球区域受损会导致阅读障碍，至少在急性期如此，不过一些个体最终能恢复阅读能力。先前的神经影像学研究表明，与对照组相比，在单词阅读任务中，阅读恢复与对侧及病灶周围激活增加之间存在关联。关于如何解释这些激活变化仍存在疑问。这些变化反映的是功能接管，即受损大脑中功能的重新组织吗？还是揭示了代偿性伪装，或者是患者和对照组都具备的用于阅读的替代神经通路的使用情况？我们通过研究一位名叫CH的个体来解决这些问题，他在中风后对熟悉单词的阅读能力有了部分恢复。我们使用一种功能磁共振成像分析技术，即表征相似性分析（RSA），它使我们能够从神经活动的分布式模式中解码认知功能。相对于对照组，我们发现CH在对侧区域从视觉加工转向了正字法加工，在病灶周围区域也有边缘显著的结果。这种模式支持中风后对侧正字法加工的重新组织。更普遍地说，这些分析证明了RSA在绘制语言功能的神经可塑性方面有多么强大。
