Kürzinger Benedikt, Schindler Stephanie, Meffert Martin, Rosenhahn Anja, Trampel Robert, Turner Robert, Schoenknecht Peter
Department of Psychiatry and Psychotherapy, University Hospital Leipzig, Leipzig, Germany.
Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Front Psychiatry. 2025 Jan 6;15:1404594. doi: 10.3389/fpsyt.2024.1404594. eCollection 2024.
The basolateral complex of the amygdala is a crucial neurobiological site for Pavlovian conditioning. Investigations into volumetric alterations of the basolateral amygdala in individuals with major depressive disorder (MDD) have yielded conflicting results. These may be reconciled in an inverted U-shape allostatic growth trajectory. This hypothesized trajectory unfolds with an initial phase of volumetric expansion, driven by enhanced dendritic arborization and synaptic plasticity. The increase in volume is followed by a reduction phase, as glucocorticoid exposure cumulatively results in excitotoxic damage, reflecting allostatic load.
7T magnetic resonance brain imaging was conducted on a total of 84 participants (mean age 38 ± 12 years), comprising 20 unmedicated and 20 medicated individuals with MDD, 21 individuals suffering from bipolar disorder and 23 healthy controls. We employed FreeSurfer 7.3.2 for automatic high-resolution segmentation of nine amygdala subnuclei. We conducted analyses of covariance, with volumes of the basolateral complex, the lateral nucleus and, exploratively, the whole amygdala, as dependent variables, while controlling for the total intracranial volume and sex. Quadratic regressions were computed within the MDD group and in relevant subgroups to investigate the presence of a U-shaped relationship between the number of preceding major depressive episodes or the duration of the disease since the first episode and the dependent variables.
Diagnostic groups did not exhibit statistically significant differences in the volumes of the basolateral amygdala (left (3,75) = 0.66, >.05; right (3,76) = 1.80, >.05), the lateral nucleus (left (3,75) = 1.22, >.05; right (3,76) = 2.30, >.05)), or the whole amygdala (left (3,75) = 0.48, >.05; right (3,76) = 1.58, >.05). No quadratic associations were observed between surrogate parameters of disease progression and any of the examined amygdala volumes. There were no significant correlations between subregion volumes and clinical characteristics.
We found no evidence for the hypothesis of an inverted U-shaped volumetric trajectory of the basolateral amygdala in MDD. Future research with larger sample sizes, including the measurement of genetic and epigenetic markers, will hopefully further elucidate this compelling paradigm.
杏仁核基底外侧复合体是经典条件反射的关键神经生物学位点。对重度抑郁症（MDD）患者杏仁核基底外侧体积变化的研究结果相互矛盾。这些结果可能在倒U形的适应性生长轨迹中得到调和。这种假设的轨迹最初是体积扩张阶段，由树突分支增加和突触可塑性驱动。体积增加之后是减少阶段，因为糖皮质激素的暴露会累积导致兴奋性毒性损伤，反映了适应性负荷。
对总共84名参与者（平均年龄38±12岁）进行了7T磁共振脑成像，其中包括20名未接受药物治疗和20名接受药物治疗的MDD患者、21名双相情感障碍患者和23名健康对照者。我们使用FreeSurfer 7.3.2对九个杏仁核亚核进行自动高分辨率分割。我们进行了协方差分析，将基底外侧复合体、外侧核以及探索性地将整个杏仁核的体积作为因变量，同时控制总颅内体积和性别。在MDD组和相关亚组中进行二次回归，以研究之前重度抑郁发作的次数或自首次发作以来疾病的持续时间与因变量之间是否存在U形关系。
诊断组在杏仁核基底外侧体积（左侧F(3,75)=0.66，p>.05；右侧F(3,76)=1.80，p>.05）、外侧核体积（左侧F(3,75)=1.22，p>.05；右侧F(3,76)=2.30，p>.05）或整个杏仁核体积（左侧F(3,75)=0.48，p>.05；右侧F(3,76)=1.58，p>.05）方面没有表现出统计学上的显著差异。在疾病进展的替代参数与任何检查的杏仁核体积之间未观察到二次关联。亚区域体积与临床特征之间没有显著相关性。
我们没有发现证据支持MDD中杏仁核基底外侧体积呈倒U形轨迹的假设。未来使用更大样本量的研究，包括测量遗传和表观遗传标记，有望进一步阐明这一引人注目的范式。
