Department of Radiology, University of Washington, Seattle, WA 98195, USA.
Compr Psychiatry. 2012 Aug;53(6):706-17. doi: 10.1016/j.comppsych.2011.11.006. Epub 2011 Dec 27.
The objectives of this study are to investigate the neuroanatomy, regional brain connectivity, and neurochemistry of a prodigious artistic savant; to place these findings within the context of existing neuroimaging literature of savant syndrome; and to discuss the utility of newer imaging modalities to extend our current understanding of mechanisms underlying savant skills.
High-resolution magnetic resonance (MR) imaging, J-resolved MR spectroscopy, and diffusion tensor imaging data were acquired during a single scanning session for a 63-year-old male autistic savant with prodigious artistic skills. Regional and compartmental brain volumes, N-acetyl aspartate, choline, creatine, glutamate and γ-aminobutyric acid concentrations, fractional anisotropy values, and white matter bundle volumes as well as axial, radial, and mean diffusivities were calculated.
No gross anatomical differences were observed. By morphological assessment, cerebral volume (1362 mL) was larger than normative literature values for adult males. The corpus callosum was intact and did not exhibit abnormal structural features. The right cerebral hemisphere was 1.9% larger than the left hemisphere; the right amygdala and right caudate nuclei were 24% and 9.9% larger, respectively, compared with the left side. In contrast, the putamen was 8.3% larger on the left side. Fractional anisotropy was increased on the right side as compared with the left for 4 of the 5 bilateral regions studied (the amygdala, caudate, frontal lobe, and hippocampus). Fiber tract bundle volumes were larger on the right side for the amygdala, hippocampus, frontal lobe, and occipital lobe. Both the left and the right hippocampi had substantially increased axial and mean diffusivities as compared with those of a comparison sample of nonsavant adult males. The corpus callosum and left amygdala also exhibited high axial, radial, and mean diffusivities. MR spectroscopy revealed markedly decreased γ-aminobutyric acid and glutamate in the parietal lobe.
Although examination of brain gross morphometry demonstrated no clinically remarkable abnormalities, utilization of conventional as well as newer MR imaging technologies revealed several atypical structural and chemical features that may be involved in the special skills of this prodigious savant. The multimodal imaging approach presented in this study is suitable for the evaluation of larger samples of savants with a diverse range of talents to investigate common brain features that may underlie the exceptional cognitive capabilities characteristic of savant syndrome. Given the high co-occurrence of the two syndromes, elucidating the underlying neurophysiologic basis of savant syndrome may also lead to a better understanding of autism spectrum disorder.
本研究旨在探讨一位非凡艺术天才的神经解剖结构、局部脑连接和神经化学，将这些发现置于学者症候群的现有神经影像学文献背景下，并讨论新的成像方式如何扩展我们对学者症候群相关技能机制的现有理解。
对一名 63 岁男性自闭症学者症候群患者进行单次扫描，获取高分辨率磁共振（MR）成像、J 分辨磁共振波谱和弥散张量成像数据。计算局部和分室脑容量、N-乙酰天门冬氨酸、胆碱、肌酸、谷氨酸和γ-氨基丁酸浓度、各向异性分数值以及白质束体积、轴向、径向和平均弥散度。
未观察到明显的大体解剖差异。通过形态学评估，脑体积（1362ml）大于成年男性的文献正常值。胼胝体完整，无异常结构特征。右大脑半球比左大脑半球大 1.9%；右侧杏仁核和右侧尾状核分别比左侧大 24%和 9.9%。相比之下，左侧壳核大 8.3%。与左侧相比，右侧的 5 个双侧区域（杏仁核、尾状核、额叶和海马体）中的 4 个区域的各向异性分数增加。与右侧相比，右侧的杏仁核、海马体、额叶和枕叶的纤维束体积更大。左侧和右侧的海马体与非学者症候群成年男性的比较样本相比，轴向和平均弥散度显著增加。胼胝体和左侧杏仁核也表现出高轴向、径向和平均弥散度。磁共振波谱显示顶叶的γ-氨基丁酸和谷氨酸明显减少。
尽管对大脑大体形态的检查未发现明显的临床异常，但常规和新的磁共振成像技术的应用显示出一些可能与这位非凡学者的特殊技能相关的非典型结构和化学特征。本研究中提出的多模态成像方法适用于对具有不同才能的大量学者进行评估，以研究可能构成学者症候群特征的异常认知能力的共同大脑特征。鉴于这两种综合征的高共发性，阐明学者症候群的潜在神经生理基础也可能有助于更好地理解自闭症谱系障碍。
