Schizophrenia (SZ) is proposed as a disorder of dysconnectivity underlying cognitive impairments and clinical manifestations. Although previous studies have shown extracellular changes in white matter of first-episode SZ, little is known about the transition period towards chronicity and its association with cognition. Free-water (FW) imaging was applied to 79 early course SZ participants and 29 controls to detect white matter axonal and extracellular differences during this phase of illness. Diffusion-weighted images were collected from two sites, harmonized, and processed using a pipeline separately modeling water diffusion in tissue (FAt) and extracellular space (FW). Tract-Based Spatial Statistics was performed using the ENIGMA-DTI protocols. SZ showed FAt reductions in the posterior thalamic radiation (PTR) and FW elevations in the cingulum compared to controls, suggesting FAt and FW changes in the early course of SZ. In SZ, greater FAt of the fornix & stria terminalis (FXST) was positively associated with Theory of Mind performance; average whole-brain FAt, FAt of the FXST and the PTR were positively associated with greater working memory performance; average whole-brain FAt was positively associated with visual learning. Further studies are necessary to better understand the neurobiological mechanisms of SZ for developing intervention strategies to preserve brain structure and function.

中文翻译：

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白质微结构和细胞外游离水与精神分裂症早期认知能力的关系

精神分裂症 (SZ) 被认为是一种潜在的认知障碍和临床表现的连接障碍疾病。尽管先前的研究表明首发 SZ 的白质发生细胞外变化，但对于向慢性化的过渡期及其与认知的关系知之甚少。自由水 (FW) 成像应用于 79 名早期 SZ 参与者和 29 名对照，以检测该疾病阶段期间的白质轴突和细胞外差异。从两个站点收集扩散加权图像，使用管道分别对组织 (FAt) 和细胞外空间 (FW) 中的水扩散进行建模和处理。使用 ENIGMA-DTI 协议执行基于区域的空间统计。与对照组相比，SZ 显示后丘脑辐射 (PTR) 和 FW 升高的 FAt 减少，表明 SZ 早期过程中 FAt 和 FW 发生变化。在 SZ，更大的穹窿和终纹 (FXST) 脂肪与心理理论表现呈正相关；平均全脑脂肪、FXST 和 PTR 的脂肪与更好的工作记忆表现呈正相关；平均全脑脂肪与视觉学习呈正相关。需要进一步研究以更好地了解 SZ 的神经生物学机制，以制定干预策略以保护大脑结构和功能。终纹 (FXST) 与心理理论表现呈正相关；平均全脑脂肪、FXST 和 PTR 的脂肪与更好的工作记忆表现呈正相关；平均全脑脂肪与视觉学习呈正相关。需要进一步研究以更好地了解 SZ 的神经生物学机制，以制定干预策略以保护大脑结构和功能。终纹 (FXST) 与心理理论表现呈正相关；平均全脑脂肪、FXST 和 PTR 的脂肪与更好的工作记忆表现呈正相关；平均全脑脂肪与视觉学习呈正相关。需要进一步研究以更好地了解 SZ 的神经生物学机制，以制定干预策略以保护大脑结构和功能。