Objective: The functions of both the central and peripheral autonomic nervous system, indexed by heart rate variability (HRV), are affected by psychology and physiology. This review summarizes the results of studies comparing the evaluation of HRV parameters between individuals with posttraumatic stress disorder (PTSD) and healthy controls. Methods: Eligible studies (n=499) were identified through literature searches of the EMBASE, Medline, PubMed and Web of Science databases. Nineteen studies met our inclusion criteria. A random effects model was used, and standardized mean differences for highfrequency HRV(HF-HRV), low-frequency HRV(LF-HRV) and the root mean square of successive R-R interval differences (RMSSD) were calculated. Results: Significant effects were found for HF-HRV [p<0.0001, Z=4.18; Hedges’g=-1.58, 95% confidence interval (CI) (-2.32, -0.84); k=14] and RMSSD [p<0.00001, Z=4.80; Hedges’g=-1.96, 95% CI (-2.76, -1.16); k=9] relative to healthy controls. Considerable heterogeneity was revealed, but the main effects for HF-HRV and RMSSD were robust in subsequent meta-regression and subgroup analyses. Conclusion Given the relationships among low vagal state, inflammation, and alterations in brain structure and function, including executive function and emotion regulation, reduced HRV may be regarded as an endophenotype in PTSD research.

BackgroundThe activity in precuneus within default mode network has been reported to be associated with antidepressant response， whereas the relationship between the functional network of precuneus and early response to antidepressant medications remains unclear. ObjectiveTo investigate the relationship between precuneus functional connectivity （FC） and early efficacy of antidepressant treatment in patients with major depressive disorder， so as to find a neurobiomarker to predict the early efficacy of antidepressants. MethodsA consecutive sample of 47 patients with major depressive disorder who attended the Mental Health Center， West China Hospital of Sichuan University from July 2017 to February 2019 and fulfilled the diagnostic criteria of Diagnostic and Statistical Manual of Mental Disorders， fifth edition （DSM-5） were recruited. Baseline resting-state functional magnetic resonance imaging scan findings and clinical assessments were recorded in participants. All patients treated with antidepressants for two weeks. Improvement was defined as 20% or greater reduction in baseline 16-item Quick Inventory of Depressive Symptoms Self-Report Scale （QIDS-SR16） by treatment exit， and patients were then classified into early improved group （n=27） and non-improved group （n=20）. FC values of precuneus and whole brain were calculated using bilateral precuneus as seed region， and baseline precuneus FC values were compared between two groups. Pearson correlation analysis was utilized to explore the correlation between FC values in brain regions with statistically significant differences and QIDS-SR16 total scores and reduction rates. ResultsFC values between the left precuneus and left precentral gyrus and between the right precuneus and right fusiform gyrus in early improved group were both higher than those in non-improved group （GRF correction， P<0.01）. The FC valves between the left precuneus and the left precentral gyrus and between the right precuneus and the right fusiform gyrus were positively correlated with QIDS-SR16 reduction rate （r=0.475， 0.297， P<0.05）. ConclusionWeakened FC between the left precuneus and left precentral gyrus and between the right precuneus and right fusiform gyrus are related to poor early efficacy to antidepressant treatment， and FC of precuneus may be a potential predictor of early response to antidepressants. ［Funded by the National Key Research & Development Program of China （number， 2016YFC1307204）； Key Development Project of the Sichuan Provincial Science and Technology Plan （number， 2018SZ0131）］