Nosarti Chiara, Shergill Sukhwinder S, Allin Matthew P, Walshe Muriel, Rifkin Larry, Murray Robin M, McGuire Philip K
Department of Psychiatry, Biomedical Research Centre for Mental Health, Institute of Psychiatry and King's College London, London, UK.
Neuroimage. 2009 Oct 1;47(4):1904-13. doi: 10.1016/j.neuroimage.2009.04.041. Epub 2009 Apr 17.
Several studies have described poorer performance in executive-type tasks in individuals who were born very preterm compared to controls. As there is evidence that high-order executive functions may be underpinned by neuronal activity in frontal-striatal circuits, we investigated with functional MRI a group of young adults who were born very preterm (n=28, gestational age <33 weeks) and controls (n=26) in order to detect possible alterations in brain activation during completion of a letter fluency task with differential cognitive loading ("easy" and "hard" letter trials). Structural MRI data were also collected to clarify whether any functional changes were associated with structural brain volume changes. Group membership, level of task difficulty and gestational age had significant effects on brain activation. In the absence of significant between-group differences in task performance, during "easy" letter trials, very preterm-born individuals showed attenuated activation in anterior cingulate gyrus, right caudate nucleus and left inferior frontal gyrus compared to controls. During "hard" letter trials, very preterm-born individuals showed both decreased and increased BOLD signal compared to controls, in left middle frontal and anterior cingulate gyrus, respectively. BOLD signal in caudate nucleus and anterior cingulate gyrus, in regions with peaks close to areas where between-group differences were observed, was linearly associated with gestational age. Analysis of structural MRI data showed altered grey matter distribution in the preterm-born group compared to controls. However, fMRI results were only partly explained by structural changes, and may reflect processes of functional plasticity for the successful completion of executive-type operations.
几项研究表明，与对照组相比，极早早产儿在执行型任务中的表现较差。由于有证据表明高阶执行功能可能由额叶-纹状体回路中的神经元活动支持，我们使用功能磁共振成像对一组极早早产的年轻成年人（n = 28，胎龄<33周）和对照组（n = 26）进行了研究，以检测在完成具有不同认知负荷的字母流畅性任务（“简单”和“困难”字母试验）期间大脑激活的可能变化。还收集了结构磁共振成像数据，以阐明任何功能变化是否与脑结构体积变化相关。组别、任务难度水平和胎龄对大脑激活有显著影响。在任务表现方面没有显著的组间差异的情况下，在“简单”字母试验期间，与对照组相比，极早早产儿在前扣带回、右侧尾状核和左侧额下回的激活减弱。在“困难”字母试验期间，与对照组相比，极早早产儿在左侧额中回和前扣带回分别表现出BOLD信号降低和增加。尾状核和前扣带回中的BOLD信号，在峰值接近观察到组间差异的区域，与胎龄呈线性相关。结构磁共振成像数据分析显示，与对照组相比，早产组的灰质分布发生了改变。然而，功能磁共振成像结果仅部分由结构变化解释，可能反映了成功完成执行型操作的功能可塑性过程。
