Levy Jonathan, Pernet Cyril, Treserras Sebastien, Boulanouar Kader, Berry Isabelle, Aubry Florent, Demonet Jean-Francois, Celsis Pierre
INSERM, U825, 31000 Toulouse, France.
Neuroimage. 2008 Nov 15;43(3):581-91. doi: 10.1016/j.neuroimage.2008.08.008. Epub 2008 Aug 22.
Neuroimaging studies of reading converge to suggest that linguistically elementary stimuli are confined to the activation of bilateral posterior regions, whereas linguistically complex stimuli additionally recruit left hemispheric anterior regions, raising the hypotheses of a gradual bilateral-to-left and a posterior-to-anterior recruitment of reading related areas. Here, we tested these two hypotheses by contrasting a repertoire of eight categories of stimuli ranging from simple orthographic-like characters to words and pseudowords in a single experiment, and by measuring BOLD signal changes and connectivity while 16 fluent readers passively viewed the stimuli. Our results confirm the existence of a bilateral-to-left and posterior-to-anterior recruitment of reading related areas, straightforwardly resulting from the increase in stimuli's linguistic processing load, which reflects reading processes: visual analysis, orthographic encoding and phonological decoding. Connectivity analyses strengthened the validity of these observations and additionally revealed an enhancement of the left parieto-frontal information trafficking for higher linguistic processing. Our findings clearly establish the notion of a gradual spatio-functional recruitment of reading areas and demonstrate, to the best of our knowledge, the first evidence of a robust and staged link between the level of linguistic processing, the spatial distribution of brain activity and its information trafficking.
阅读的神经影像学研究一致表明，语言上基本的刺激仅限于双侧后部区域的激活，而语言上复杂的刺激还会额外激活左半球前部区域，从而提出了阅读相关区域从双侧到左侧、从后部到前部逐渐激活的假设。在此，我们通过在单一实验中对比从简单的类正字法字符到单词和伪词的八类刺激，并在16名流利阅读者被动观看刺激时测量血氧水平依赖（BOLD）信号变化和连通性，来检验这两个假设。我们的结果证实了阅读相关区域从双侧到左侧、从后部到前部的激活现象，这直接源于刺激的语言处理负荷增加，而这种负荷增加反映了阅读过程：视觉分析、正字法编码和语音解码。连通性分析增强了这些观察结果的有效性，此外还揭示了在进行更高层次语言处理时，左顶叶-额叶信息传递的增强。我们的研究结果明确确立了阅读区域逐渐进行空间功能激活的概念，并据我们所知首次证明了语言处理水平、大脑活动的空间分布及其信息传递之间存在稳健且分阶段的联系。
