Faculty of Electronics and Information Technology Warsaw University of Technology, Nowowiejska 15/19, 00-665, Warsaw, Poland.
Laboratory of Brain Imaging, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093, Warsaw, Poland.
Sci Rep. 2019 Mar 25;9(1):5096. doi: 10.1038/s41598-019-41473-x.
Several etiological theories, in particular neuronal noise and impaired auditory sampling, predicted neurotransmission deficits in dyslexia. Neurometabolites also affect white matter microstructure, where abnormalities were previously reported in dyslexia. However findings from only few magnetic resonance spectroscopy studies using diverse age groups, different brain regions, data processing and reference scaling are inconsistent. We used MEGA-PRESS single-voxel spectroscopy in two ROIs: left temporo-parietal and occipital cortex in 36 adults and 52 children, where half in each group had dyslexia. Dyslexics, on average, had significantly lower total N-acetylaspartate (tNAA) than controls in the occipital cortex. Adults compared to children were characterized by higher choline and creatine in both areas, higher tNAA in left temporo-parietal and lower glutamate in the visual cortex, reflecting maturational changes in cortical microstructure and metabolism. Although the current findings do not support the proposed etiological theories of dyslexia, they show, for the first time, that tNAA, considered to be a neurochemical correlate of white matter integrity, is deficient in the visual cortex in both children and adults with dyslexia. They also point that several neurotransmitters, including ones previously used as reference, change with age.
一些病因理论，特别是神经元噪声和听觉采样受损，预测了阅读障碍中的神经递质传递缺陷。神经代谢物也会影响白质的微观结构，先前的研究已经报道了阅读障碍中的白质异常。然而，使用不同年龄组、不同脑区、数据处理和参考标度的磁共振波谱研究的结果并不一致。我们使用 MEGA-PRESS 单体素波谱在两个 ROI 中进行研究：左颞顶叶和枕叶皮层，共有 36 名成年人和 52 名儿童参与，其中每组有一半人患有阅读障碍。阅读障碍者的枕叶皮层中的总 N-乙酰天冬氨酸（tNAA）明显低于对照组。与儿童相比，成年人在两个区域中的胆碱和肌酸水平更高，左颞顶叶的 tNAA 更高，而视觉皮层中的谷氨酸更低，这反映了皮质微观结构和代谢的成熟变化。尽管目前的研究结果并不支持阅读障碍的既定病因理论，但它们首次表明，被认为是白质完整性神经化学相关物的 tNAA 在儿童和成人阅读障碍者的视觉皮层中都存在缺陷。它们还指出，包括先前用作参考的那些，一些神经递质会随年龄变化。
