Qiu Anqi, Zhong Jidan, Graham Steven, Chia Ming Ying, Sim Kang
Division of Bioengineering, National University of Singapore, Singapore.
Neuroimage. 2009 Oct 1;47(4):1163-71. doi: 10.1016/j.neuroimage.2009.04.027. Epub 2009 Apr 16.
The thalamus has been considered to be integral to the pathophysiology of schizophrenia. To determine whether its anatomical abnormalities may be associated with cognitive deficits in the onset of schizophrenia, we assessed thalamic volume, shape, white matter integrity, and their correlations with cognition in patients with first-episode schizophrenia. T1-weighted magnetic resonance and diffusion tensor (DT) images were collected in 49 healthy comparison controls (CON) and 32 patients with FES (FES). Large deformation diffeomorphic metric mapping (LDDMM) algorithms were used to delineate and assess the thalamic shape from MRI scans. The thalamic white matter integrity was quantified by fractional anisotropy (FA) and mean diffusivity (MD) averaged over the thalamus using DTI. Our analysis revealed that FES did not differ from CON in FA and MD but did differ markedly from them in the thalamic volume and shape. Patients with FES also performed poorly in spatial working memory and executive tasks. The correlation study found that regional thalamic shapes highly correlate with the two cognitive scores in the entire sample and healthy comparison controls but not in patients with FES even though no correlation was found between the thalamic volumes with the two cognitive scores in any group. Left thalamic FA was correlated with spatial working memory deficits in FES. Our findings suggest that thalamic volume and shape abnormalities are evident at the onset of FES prior to thalamic abnormal white matter integrity. Altered microstructural white matter integrity assessed using DTI may not be apparent in FES but may be observed as the disease progresses. Cognitive deficits related to spatial working memory and executive functioning in FES were observed in the context of loss of their normal relationship with the thalamic shapes, that is, regionally-specific thalamic shape compression is associated with poor performance in executive functioning and spatial working memory.
丘脑被认为在精神分裂症的病理生理学中起着不可或缺的作用。为了确定其解剖结构异常是否与精神分裂症发病时的认知缺陷相关，我们评估了首发精神分裂症患者的丘脑体积、形状、白质完整性及其与认知的相关性。对49名健康对照者（CON）和32名首发精神分裂症患者（FES）采集了T1加权磁共振成像和扩散张量（DT）图像。使用大变形微分同胚度量映射（LDDMM）算法从MRI扫描中描绘和评估丘脑形状。通过使用DTI对丘脑平均分数各向异性（FA）和平均扩散率（MD）进行量化来评估丘脑白质完整性。我们的分析显示，FES组在FA和MD方面与CON组没有差异，但在丘脑体积和形状方面与CON组有显著差异。FES患者在空间工作记忆和执行任务方面也表现不佳。相关性研究发现，在整个样本和健康对照者中，丘脑区域形状与两项认知评分高度相关，但在FES患者中并非如此，尽管在任何组中丘脑体积与两项认知评分之间均未发现相关性。左侧丘脑FA与FES患者的空间工作记忆缺陷相关。我们的研究结果表明，在丘脑白质完整性异常之前，FES发病时丘脑体积和形状异常就很明显。使用DTI评估的微观结构白质完整性改变在FES中可能不明显，但可能在疾病进展过程中观察到。在FES患者中，与空间工作记忆和执行功能相关的认知缺陷是在其与丘脑形状的正常关系丧失的背景下观察到的，即区域特异性丘脑形状压缩与执行功能和空间工作记忆表现不佳相关。
