Hippocampal circuitry has been posited to be fundamental to positive symptoms in psychosis, but its contributions to other factors important for outcome remains unclear. We hypothesized that longitudinal changes in the hippocampal circuit and concomitant changes of intracortical microstructure are altered in first episode psychosis (FEP) patients and that such changes are associated with negative symptoms and verbal memory. Longitudinal brain scans (2–4 visits over 3–15 months) were acquired for 27 FEP and 29 age‐ and sex‐matched healthy controls. Quantitative T1 maps, sensitive to myelin content, were used to sample the microstructure of the hippocampal subfields and output circuitry (fimbria, alveus, fornix, mammillary bodies), and intracortical regions. Dynamic anatomical covariance in pair‐wise regional trajectories were assessed for each subject, and graph theory was used to calculate a participation coefficient metric that quantifies the similarity/divergence between hippocampal and intracortical microstructure. The mean participation coefficient of the hippocampus was significantly reduced in FEP patients compared with controls, reflecting differences in output hippocampal regions. Importantly, lower participation coefficient of the hippocampal circuit was associated with worse negative symptoms, a relationship that was mediated by changes in verbal memory. This study provides evidence for reduced hippocampal centrality in FEP and concomitant changes in intracortical anatomy. Myelin‐rich output regions of the hippocampus may be an important biological trigger in early psychosis, with cascading effects on broader cortical networks and resultant clinical profiles.

中文翻译：

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首发精神病中海马中心性的改变和皮质内微观结构的动态解剖协方差。

海马回路被认为是精神病阳性症状的基础，但它对其他对结果重要的因素的贡献尚不清楚。我们假设首发精神病 (FEP) 患者海马回路的纵向变化和皮质内微结构的伴随变化发生了改变，并且这些变化与阴性症状和语言记忆有关。获得了 27 名 FEP 和 29 名年龄和性别匹配的健康对照的纵向脑部扫描（3-15 个月内 2-4 次访问）。使用对髓鞘含量敏感的定量 T1 图对海马亚区和输出电路（菌毛、牙槽骨、穹窿、乳头体）和皮质内区域的微观结构进行采样。对每个受试者评估成对区域轨迹中的动态解剖协方差，并使用图论计算参与系数度量，该度量量化海马和皮层内微结构之间的相似性/差异。与对照组相比，FEP 患者海马的平均参与系数显着降低，反映了输出海马区域的差异。重要的是，海马回路的较低参与系数与更严重的阴性症状相关，这种关系是由语言记忆的变化介导的。该研究为 FEP 中海马中心性降低和皮层内解剖结构的伴随变化提供了证据。海马体富含髓鞘的输出区域可能是早期精神病的重要生物学触发因素，