Ahmanson-Lovelace Brain Mapping Center in the Department of Neurology, 660 Charles Young Dr. So. Los Angeles, CA 90095, USA.
J Psychiatr Res. 2013 Apr;47(4):505-12. doi: 10.1016/j.jpsychires.2012.11.011. Epub 2012 Dec 27.
Neuroimaging studies in multiple modalities have implicated the left or right dorsolateral prefrontal cortex (here, middle frontal gyrus) in attentional functions, in ADHD, and in dopamine agonist treatment of ADHD. The far lateral location of this cortex in the brain, however, has made it difficult to study with magnetic resonance spectroscopy (MRS). We used the smaller voxel sizes of the magnetic resonance spectroscopic imaging (MRSI) variant of MRS, acquired at a steep coronal-oblique angle to sample bilateral middle frontal gyrus in 13 children and adolescents with ADHD and 13 age- and sex-matched healthy controls. Within a subsample of the ADHD patients, aspects of attention were also assessed with the Trail Making Task. In right middle frontal gyrus only, mean levels of N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (tNAA), creatine + phosphocreatine (Cr), choline-compounds (Cho), and myo-inositol (mI) were significantly lower in the ADHD than in the control sample. In the ADHD patients, lower right middle frontal Cr was associated with worse performance on Trails A and B (focused attention, concentration, set-shifting), while the opposite relationship held true for the control group on Trails B. These findings add to evidence implicating right middle frontal cortex in ADHD. Lower levels of these multiple species may reflect osmotic adjustment to elevated prefrontal cortical perfusion in ADHD and/or a previously hypothesized defect in astrocytic production of lactate in ADHD resulting in decelerated energetic metabolism (Cr), membrane synthesis (Cho, mI), and acetyl-CoA substrate for NAA synthesis. Lower Cr levels may indicate attentional or executive impairments.
多模态神经影像学研究表明，左或右背外侧前额叶皮层（此处为额中回）参与了注意力功能、ADHD 以及多巴胺激动剂治疗 ADHD。然而，该脑区在大脑中的外侧位置使得使用磁共振波谱（MRS）进行研究变得非常困难。我们使用 MRS 的磁共振波谱成像（MRSI）变体，以陡峭的冠状斜角采集 13 名 ADHD 儿童和青少年以及 13 名年龄和性别匹配的健康对照者双侧额中回的较小体素大小。在 ADHD 患者的亚组中，还使用连线测试评估了注意力的各个方面。仅在右侧额中回中，ADHD 组的 N-乙酰天冬氨酸+N-乙酰天门冬氨酸谷氨酸（tNAA）、肌酸+磷酸肌酸（Cr）、胆碱化合物（Cho）和肌醇（mI）的平均水平明显低于对照组。在 ADHD 患者中，右侧额中回 Cr 水平越低，Trails A 和 B（集中注意力、注意力、转换能力）的表现越差，而对照组的情况则相反。这些发现为右额中回在 ADHD 中的作用提供了更多证据。这些多种物质水平较低可能反映了 ADHD 患者前额皮质灌注升高的渗透压调节，以及之前假设的星形胶质细胞在 ADHD 中产生乳酸的缺陷导致能量代谢（Cr）、膜合成（Cho、mI）和 NAA 合成的乙酰辅酶 A 底物（Cr）减速。Cr 水平较低可能表明注意力或执行功能受损。
