Zeng Can, Xue Zhimin, Ross Brendan, Zhang Manqi, Liu Zhening, Wu Guowei, Ouyang Xuan, Li Dan, Pu Weidan
Department of Psychiatry, the Second Xiangya Hospital, Central South University,Changsha, China; The China National Clinical Research Center for Mental Health Disorders, Changsha, China; China National Technology Institute on Mental Disorders, Changsha, China; Hunan Key Laboratory of Psychiatry and Mental Health, Changsha, China; Mental Health Institute of Central South University, Changsha, China; Education college, Shaoguan University, Shaoguan, China.
Department of Psychiatry, the Second Xiangya Hospital, Central South University,Changsha, China; The China National Clinical Research Center for Mental Health Disorders, Changsha, China; China National Technology Institute on Mental Disorders, Changsha, China; Hunan Key Laboratory of Psychiatry and Mental Health, Changsha, China; Mental Health Institute of Central South University, Changsha, China.
J Affect Disord. 2020 May 15;269:43-50. doi: 10.1016/j.jad.2020.03.007. Epub 2020 Mar 3.
Bipolar depression (BDD) and major depressive disorder (MDD) are two diseases both characterized by depressed mood and diminished interest or pleasure. Recent neuroimaging studies have implicated the thalamo-cortical circuit in mood disorders, and the present study aimed to map thalamo-cortical connectivity to explore the dissociable and common abnormalities between bipolar and major depression in this circuit.
Applying resting-state functional magnetic resonance imaging (fMRI), we mapped the thalamo-cortical circuit using a fine-grained thalamic atlas with 8 sub-regions bilaterally in 38 BDD patients, 42 MDD patients and 39 healthy controls (HCs). Correlation analysis was then performed between thalamo-cortical connectivity and clinical variables.
The findings showed that both patient groups exhibited prefronto-thalamo-cerebellar and sensorimotor-thalamic hypoconnectivity, while the abnormalities in MDD were more extensive. Particularly, MDD group showed decreased thalamic connectivity with the salience network including the insula, anterior cingulate cortex (ACC), and striatum. No correlations were found between the abnormal thalamo-cortical connectivity and clinical symptoms in either patient group.
Most patients in our study were taking drugs at the time of scanning, which may confound our findings.
Our finding suggest that the thalamo-cortical hypofunction is a common neuro-substrate for BDD and MDD. Specifically, the hypoconnectivity between the thalamus and salience network including the insula, ACC and striatum may be a distinguished biomarker for MDD, which may help to differentiate these two emotional disorders.
双相抑郁（BDD）和重度抑郁障碍（MDD）是两种均以情绪低落、兴趣或愉悦感减退为特征的疾病。近期的神经影像学研究表明丘脑 - 皮质回路与情绪障碍有关，本研究旨在描绘丘脑 - 皮质连接性，以探索该回路中双相抑郁和重度抑郁之间可分离的及共同的异常情况。
应用静息态功能磁共振成像（fMRI），我们使用一个双侧具有8个亚区的精细丘脑图谱，对38例双相抑郁患者、42例重度抑郁患者和39名健康对照者（HCs）的丘脑 - 皮质回路进行描绘。然后进行丘脑 - 皮质连接性与临床变量之间的相关性分析。
研究结果显示，两个患者组均表现出前额叶 - 丘脑 - 小脑及感觉运动 - 丘脑低连接性，而重度抑郁的异常情况更广泛。特别是，重度抑郁组显示丘脑与包括脑岛、前扣带回皮质（ACC）和纹状体在内的突显网络的连接性降低。在两个患者组中，异常的丘脑 - 皮质连接性与临床症状之间均未发现相关性。
我们研究中的大多数患者在扫描时正在服药，这可能会混淆我们的研究结果。
我们的研究结果表明，丘脑 - 皮质功能减退是双相抑郁和重度抑郁的共同神经基础。具体而言，丘脑与包括脑岛、ACC和纹状体在内的突显网络之间的低连接性可能是重度抑郁的一个独特生物标志物，这可能有助于区分这两种情绪障碍。
