Automatic assessment of somatic depressive symptoms from physiological signals

为了制定早期预防重度抑郁症的策略，确定抑郁状态的生物标志物和揭示重度抑郁症的发展模式至关重要。躯体抑郁症状和脑内感受网络（BIN）关键区域脑岛结构和功能的改变被认为是MDD后期发展的预测因子。然而，自主调节和内感受的异常是否与MDD中BIN的改变有关尚不清楚。这个为期两年的项目旨在开发评估躯体症状的生物标志物，并研究潜在的神经机制。在第一年，从磁共振成像数据中识别出躯体症状的神经标志物，并将其与异常的心脏自主调节联系起来。包括扣带、眶额皮质、脑岛和海马在内的12个BIN区域的体积与躯体抑郁症状呈负相关。在66个功能连通性（FCs）中，28个FCs的组合预测准确率最高（相关性=0.805,p<0.01）。其中，MDD患者脑岛与前扣带皮层（ACC）之间的4个FCs显著低于HC。此外，连通性的减少与搏动间隔变异性的减少以及心脏交感和副交感神经活动的减少有关。结果表明，脑岛和ACC结构和功能的改变可能是在MDD的发展和缓解中起关键作用的躯体和自主神经异常的基础。

To develop strategies for early prevention of MDD, it is crucial to identify biomarkers for depressive state and uncover the development model of MDD. Somatic depressive symptoms and the alterations of structure and functions in insula, the key region of brain interoceptive network (BIN), were reported as predictors of later development of MDD. However, it remained unclear whether the abnormalities of autonomic regulation and interoception are linked to the alterations of BIN in MDD. This two-year project aims to develop biomarkers for assessment of somatic symptoms and investigate the underlying neural mechanisms.In the first year, the neuromarkers for somatic symptoms were identified from magnetic resonance imaging data and linked to the abnormal cardiac autonomic regulation. The volume of 12 BIN regions including the cingulate, orbital frontal cortex, insula, and hippocampus were negatively correlated with somatic depressive symptoms. Among the 66 functional connectivity (FCs), a combination of 28 FCs achieved the highest prediction accuracy (correlation=0.805, p<0.01). Among them, 4 FCs between insula and anterior cingulate cortex (ACC) were significantly lower in MDD patients than in HC. Moreover, the reduced connectivity was correlated with decreased variability in inter-beat interval and decreased cardiac sympathetic and parasympathetic activity. The results suggest that alterations in the structure and function of the insula and ACC may underlie the somatic and autonomic abnormalities that play crucial roles in the development and remission of MDD.