Little is known about the neural correlates of dissociative amnesia, a transdiagnostic symptom mostly present in the dissociative disorders and core characteristic of dissociative identity disorder (DID). Given the vital role of the hippocampus in memory, a prime candidate for investigation is whether total and/or subfield hippocampal volume can serve as biological markers of dissociative amnesia.

A total of 75 women, 32 with DID and 43 matched healthy controls (HC), underwent structural magnetic resonance imaging (MRI). Using Freesurfer (version 6.0), volumes were extracted for bilateral global hippocampus, cornu ammonis (CA) 1–4, the granule cell molecular layer of the dentate gyrus (GC-ML-DG), fimbria, hippocampal−amygdaloid transition area (HATA), parasubiculum, presubiculum and subiculum. Analyses of covariance showed volumetric differences between DID and HC. Partial correlations exhibited relationships between the three factors of the dissociative experience scale scores (dissociative amnesia, absorption, depersonalisation/derealisation) and traumatisation measures with hippocampal global and subfield volumes.

Hippocampal volumes were found to be smaller in DID as compared with HC in bilateral global hippocampus and bilateral CA1, right CA4, right GC-ML-DG, and left presubiculum. Dissociative amnesia was the only dissociative symptom that correlated uniquely and significantly with reduced bilateral hippocampal CA1 subfield volumes. Regarding traumatisation, only emotional neglect correlated negatively with bilateral global hippocampus, bilateral CA1, CA4 and GC-ML-DG, and right CA3.

We propose decreased CA1 volume as a biomarker for dissociative amnesia. We also propose that traumatisation, specifically emotional neglect, is interlinked with dissociative amnesia in having a detrimental effect on hippocampal volume.

人们对解离性遗忘症的神经相关性知之甚少，解离性遗忘症是一种跨诊断症状，主要存在于解离性障碍和解离性身份障碍 (DID) 的核心特征中。鉴于海马体在记忆中的重要作用，一个主要的研究对象是海马体总体积和/或海马体亚区体积是否可以作为分离性遗忘症的生物标志物。

共有 75 名女性，其中 32 名患有 DID 和 43 名匹配的健康对照 (HC)，接受了结构磁共振成像 (MRI)。使用 Freesurfer（6.0 版），提取了双侧全海马体、海马体（CA）1-4、齿状回颗粒细胞分子层（GC-ML-DG）、伞状体、海马体-杏仁核过渡区（HATA）的体积), parasubiculum, presubiculum 和 subiculum。协方差分析显示 DID 和 HC 之间存在体积差异。部分相关性显示了分离性体验量表分数（分离性遗忘、吸收、人格解体/现实解体）的三个因素与海马整体和子区域体积的创伤测量之间的关系。

在双侧全海马体和双侧 CA1、右侧 CA4、右侧 GC-ML-DG 和左侧前托下部，与 HC 相比，DID 中的海马体积更小。分离性遗忘症是唯一与双侧海马 CA1 子区体积减少显着相关的分离性症状。关于创伤，只有情绪忽视与双侧全球海马体、双侧 CA1、CA4 和 GC-ML-DG 以及右侧 CA3 呈负相关。

我们建议将减少的 CA1 体积作为分离性遗忘症的生物标志物。我们还提出，创伤，特别是情感忽视，与分离性遗忘症相互关联，对海马体积产生不利影响。