Lee Won, Park Hyungyou, Moon Sun-Young, Oh Sanghoon, Lee Junhee, Kim Minah, Kwon Jun Soo
Department of Brain and Cognitive Sciences, Seoul National University College of Natural Sciences, Seoul, Republic of Korea.
Department of Psychiatry, Hallym University Kangnam Sacred Heart Medical Center, Seoul, Republic of Korea.
Psychiatry Investig. 2023 Jun;20(6):550-558. doi: 10.30773/pi.2022.0334. Epub 2023 Jun 21.
The cerebello-thalamic tract is the only efferent white matter (WM) bundle of the cerebellum that connects the cerebellum to the thalamus and has recently attracted much attention in obsessive-compulsive disorder (OCD) with its integral role in higher order cognitive functions commonly impaired in OCD patients. Previous neuroimaging studies have shown that the cerebello-thalamic circuit is functionally impaired in OCD patients. However, the WM integrity of the cerebello-thalamic tract in OCD, which may underly functional abnormalities of the cerebello-thalamic circuit, is not yet sufficiently understood. Therefore, the current study aimed to elucidate whether compromised cerebello-thalamic WM integrity is observed in medication-free OCD patients.
In this study, diffusion tensor imaging was acquired from 106 medication-free OCD patients and 105 matched healthy controls (HCs). Probabilistic tractography was then used to reconstruct the cerebello-thalamic tract with accurate anatomical features. Three diffusion indices (fractional anisotropy, FA; mean diffusivity, MD; radial diffusivity, RD) were measured from the reconstructed bilateral cerebello-thalamic tract and then compared between groups.
We found that patients with OCD showed significantly increased MD and RD in the right cerebello-thalamic tract compared to HCs, and there was no difference in FA between groups.
Our findings may indicate the underlying structural abnormalities of the dysfunctional cerebello-thalamic circuit in OCD patients. Therefore, our findings are expected to provide novel insights into the pathophysiology of OCD on the cerebello-thalamic WM architecture, extending our knowledge from the existing functional neurobiological model of OCD.
小脑丘脑束是小脑唯一的传出白质束，它将小脑与丘脑相连，最近在强迫症（OCD）中备受关注，因为它在强迫症患者普遍受损的高阶认知功能中起着不可或缺的作用。先前的神经影像学研究表明，强迫症患者的小脑丘脑回路功能受损。然而，强迫症中小脑丘脑束的白质完整性，这可能是小脑丘脑回路功能异常的基础，尚未得到充分了解。因此，本研究旨在阐明未服药的强迫症患者是否存在小脑丘脑白质完整性受损的情况。
在本研究中，对106名未服药的强迫症患者和105名匹配的健康对照者（HCs）进行了扩散张量成像。然后使用概率性纤维束成像技术重建具有准确解剖特征的小脑丘脑束。从重建的双侧小脑丘脑束中测量三个扩散指标（分数各向异性，FA；平均扩散率，MD；径向扩散率，RD），然后在组间进行比较。
我们发现，与健康对照者相比，强迫症患者右侧小脑丘脑束的MD和RD显著增加，且组间FA无差异。
我们的研究结果可能表明强迫症患者功能失调的小脑丘脑回路存在潜在的结构异常。因此，我们的研究结果有望为强迫症在小脑丘脑白质结构方面的病理生理学提供新的见解，扩展我们从现有的强迫症功能性神经生物学模型中获得的知识。
