Structural covariance network of the hippocampus-amygdala complex in medication-naïve patients with first-episode major depressive disorder

Lianqing Zhang; Xinyue Hu; Yongbo Hu; Mengyue Tang; Hui Qiu; Ziyu Zhu; Yingxue Gao; Hailong Li; Weihong Kuang; Weidong Ji

doi:10.1093/psyrad/kkac023

Structural covariance network of the hippocampus-amygdala complex in medication-naïve patients with first-episode major depressive disorder

Psychoradiology. 2022 Dec 15;2(4):190-198. doi: 10.1093/psyrad/kkac023. eCollection 2022 Dec.

Authors

Lianqing Zhang¹, Xinyue Hu², Yongbo Hu³, Mengyue Tang¹, Hui Qiu², Ziyu Zhu¹, Yingxue Gao¹, Hailong Li¹, Weihong Kuang³, Weidong Ji^{4

5}

Affiliations

¹ Functional and molecular imaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, Chengdu 610041, PR China.
² Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, PR China.
³ Department of Psychiatry, West China Hospital of Sichuan University, Chengdu 610041, PR China.
⁴ Shanghai Key Laboratory of Mental Health and Psychological Crisis Intervention, School of Psychology and Cognitive Science and Affiliated Mental Health Center, East China Normal University, Shanghai 200335, China.
⁵ Child Psychiatry, Shanghai Changning Mental Health Center, Shanghai 200335, China.

Abstract

Background: The hippocampus and amygdala are densely interconnected structures that work together in multiple affective and cognitive processes that are important to the etiology of major depressive disorder (MDD). Each of these structures consists of several heterogeneous subfields. We aim to explore the topologic properties of the volume-based intrinsic network within the hippocampus-amygdala complex in medication-naïve patients with first-episode MDD.

Methods: High-resolution T1-weighted magnetic resonance imaging scans were acquired from 123 first-episode, medication-naïve, and noncomorbid MDD patients and 81 age-, sex-, and education level-matched healthy control participants (HCs). The structural covariance network (SCN) was constructed for each group using the volumes of the hippocampal subfields and amygdala subregions; the weights of the edges were defined by the partial correlation coefficients between each pair of subfields/subregions, controlled for age, sex, education level, and intracranial volume. The global and nodal graph metrics were calculated and compared between groups.

Results: Compared with HCs, the SCN within the hippocampus-amygdala complex in patients with MDD showed a shortened mean characteristic path length, reduced modularity, and reduced small-worldness index. At the nodal level, the left hippocampal tail showed increased measures of centrality, segregation, and integration, while nodes in the left amygdala showed decreased measures of centrality, segregation, and integration in patients with MDD compared with HCs.

Conclusion: Our results provide the first evidence of atypical topologic characteristics within the hippocampus-amygdala complex in patients with MDD using structure network analysis. It provides more delineate mechanism of those two structures that underlying neuropathologic process in MDD.

Keywords: Major depressive disorder; global network metrics; hippocampus–amygdala complex; local network metrics; structural covariance network.