Rusconi Elena, Pinel Philippe, Eger Evelyn, LeBihan Denis, Thirion Bertrand, Dehaene Stanislas, Kleinschmidt Andreas
Institut Nationale de la Santé et de la Recherche Médicale (INSERM), Unité 562, Gif-sur-Yvette, France.
Ann Neurol. 2009 Nov;66(5):654-62. doi: 10.1002/ana.21776.
To examine the functional neuroanatomy that could account for pure Gerstmann syndrome, which is the selective association of acalculia, finger agnosia, left-right disorientation, and agraphia.
We used structural and functional neuroimaging at high spatial resolution in healthy subjects to seek a shared cortical substrate of the Grundstörung posited by Gerstmann, ie, a common functional denominator accounting for this clinical tetrad. We construed a functional activation paradigm that mirrors each of the four clinical deficits in Gerstmann syndrome and determined cortical activation patterns. We then applied fiber tracking to diffusion tensor images and used cortical activation foci in the four functional domains as seed regions.
None of the subjects showed parietal overlap of cortical activation patterns from the four cognitive domains. In every subject, however, the parietal activation patterns across all four domains consistently connected to a small region of subcortical parietal white matter at a location that is congruent with the lesion in a well-documented case of pure Gerstmann syndrome.
Our functional neuroimaging findings are not in agreement with Gerstmann's postulate of damage to a common cognitive function underpinning clinical semiology. Our evidence from intact functional neuroanatomy suggests that pure forms of Gerstmann's tetrad do not arise from lesion to a shared cortical substrate but from intraparietal disconnection after damage to a focal region of subcortical white matter.
研究能够解释纯格斯特曼综合征的功能性神经解剖结构，纯格斯特曼综合征是失算症、手指失认症、左右定向障碍和失写症的选择性关联。
我们在健康受试者中使用高空间分辨率的结构和功能神经成像技术，以寻找格斯特曼提出的基本障碍的共同皮质基质，即解释这一临床四联症的共同功能要素。我们构建了一个功能性激活范式，该范式反映了格斯特曼综合征的四种临床缺陷，并确定了皮质激活模式。然后，我们将纤维追踪应用于扩散张量图像，并将四个功能域中的皮质激活灶用作种子区域。
没有受试者在四个认知域的皮质激活模式中表现出顶叶重叠。然而，在每个受试者中，所有四个域的顶叶激活模式始终连接到皮质下顶叶白质的一个小区域，该区域与一个记录良好的纯格斯特曼综合征病例中的病变位置一致。
我们的功能性神经成像结果与格斯特曼关于损害支撑临床症状学的共同认知功能的假设不一致。我们来自完整功能性神经解剖结构的证据表明，纯形式的格斯特曼四联症并非源于对共同皮质基质的损伤，而是源于皮质下白质局灶性区域损伤后的顶内连接中断。
