Psychology Department, Hebrew University, Jerusalem, Israel.
Cortex. 2011 Feb;47(2):202-16. doi: 10.1016/j.cortex.2009.12.003. Epub 2009 Dec 29.
Characterizing and mapping the relationship between neuronal reorganization and functional recovery are essential to the understanding of cerebral plasticity and the dynamic processes which occur following brain damage. The neuronal mechanisms underlying linguistic recovery following left hemisphere (LH) lesions are still unknown. Using functional magnetic resonance imaging (fMRI), we investigated whether the extent of brain lateralization of linguistic functioning in specific regions of interest (ROIs) is correlated with the level of linguistic performance following recovery from acquired childhood aphasia. The study focused on a rare group of children in whom lesions occurred after normal language acquisition, but prior to complete maturation of the brain. During fMRI scanning, rhyming, comprehension and verb generation activation tasks were monitored. The imaging data were evaluated with reference to linguistic performance measured behaviorally during imaging, as well as outside the scanner. Compared with normal controls, we found greater right hemisphere (RH) lateralization in patients. However, correlations with linguistic performance showed that increased proficiency in linguistic tasks was associated with greater lateralization to the LH. These results were replicated in a longitudinal case study of a patient scanned twice, 3 years apart. Additional improvement in linguistic performance of the patient was accompanied by increasing lateralization to the LH in the anterior language region. This, however, was the result of a decreased involvement of the RH. These findings suggest that recovery is a dynamic, ongoing process, which may last for years after onset. The role of each hemisphere in the recovery process may continuously change within the chronic stage.
描述和绘制神经元重组与功能恢复之间的关系对于理解大脑可塑性以及脑损伤后发生的动态过程至关重要。左半球（LH）损伤后语言恢复的神经元机制尚不清楚。本研究使用功能磁共振成像（fMRI），研究了特定感兴趣区域（ROI）的语言功能大脑偏侧化程度是否与获得性儿童失语症恢复后的语言表现水平相关。该研究集中在一组罕见的儿童中，他们的损伤发生在正常语言习得之后，但在大脑完全成熟之前。在 fMRI 扫描期间，监测押韵、理解和动词生成激活任务。将成像数据与在成像过程中以及在扫描仪外通过行为测量的语言表现进行评估。与正常对照组相比，我们发现患者的右半球（RH）偏侧化程度更大。然而，与语言表现的相关性表明，语言任务的熟练程度提高与左半球的偏侧化程度更高相关。这一结果在对一名患者进行的两次纵向案例研究中得到了复制，两次扫描相隔 3 年。患者的语言表现有进一步的改善，同时语言前区的左半球偏侧化程度也增加了。然而，这是由于 RH 的参与度降低所致。这些发现表明，恢复是一个动态的、持续的过程，可能在发病后持续多年。每个半球在恢复过程中的作用可能在慢性阶段不断变化。
