Duran Fabio Luis de Souza, Hoexter Marcelo Queiroz, Valente Antonio Augusto, Miguel Euripedes Constantino, Busatto Geraldo Filho
Department and Institute of Psychiatry, Clinical Hospital, University of São Paulo Medical School, SP, Brazil.
Neurosci Lett. 2009 Mar 6;452(1):68-71. doi: 10.1016/j.neulet.2009.01.007. Epub 2009 Jan 9.
Neurobiological models support an involvement of white matter tracts in the pathophysiology of obsessive-compulsive disorder (OCD), but there has been little systematic evaluation of white matter volumes in OCD using magnetic resonance imaging (MRI). We investigated potential differences in the volume of the cingulum bundle (CB) and anterior limb of internal capsule (ALIC) in OCD patients (n=19) relative to asymptomatic control subjects (n=15). White matter volumes were assessed using a 1.5T MRI scanner. Between-group comparisons were carried out after spatial normalization and image segmentation using optimized voxel-based morphometry. Correlations between regional white matter volumes in OCD subjects and symptom severity ratings were also investigated. We found significant global white matter reductions in OCD patients compared to control subjects. The voxel-based search for regional abnormalities (with covariance for total white matter volumes) showed no specific white matter volume deficits in brain portions predicted a priori to be affected in OCD (CB and ALIC). However, large clusters of significant positive correlation with OCD severity scores were found bilaterally on the ALIC. These findings provide evidence of OCD-related ALIC abnormalities and suggest a connectivity dysfunction within frontal-striatal-thalamic-cortical circuits. Further studies are warranted to better define the role of such white matter alterations in the pathophysiology of OCD, and may provide clues for a more effectively targeting of neurosurgical treatments for OCD.
神经生物学模型支持白质束参与强迫症（OCD）的病理生理学过程，但使用磁共振成像（MRI）对OCD患者的白质体积进行系统评估的研究较少。我们调查了19例OCD患者相对于15例无症状对照受试者扣带束（CB）和内囊前肢（ALIC）体积的潜在差异。使用1.5T MRI扫描仪评估白质体积。在使用优化的基于体素的形态学方法进行空间归一化和图像分割后，进行组间比较。还研究了OCD受试者区域白质体积与症状严重程度评分之间的相关性。我们发现与对照受试者相比，OCD患者存在显著的全脑白质减少。基于体素搜索区域异常情况（考虑全脑白质体积的协变量）显示，在先前预测OCD会受影响的脑区（CB和ALIC）中，未发现特定的白质体积缺陷。然而，在双侧ALIC发现了与OCD严重程度评分显著正相关的大簇区域。这些发现为与OCD相关的ALIC异常提供了证据，并提示额叶-纹状体-丘脑-皮质回路存在连接功能障碍。有必要进行进一步研究以更好地确定这种白质改变在OCD病理生理学中的作用，并可能为更有效地针对OCD的神经外科治疗提供线索。
