Effects of childhood trauma on aggressive behaviors andhippocampal function:the modulation of COMT haplotypes

Background:Aggression is a commonly hostile behavior linked to the hippocampal activity.Childhood trauma(CT)exposure has been associated with altered sensitization of the hypothalamic-pituitary-adrenal(HPA)axis and hippocampal volumewhich could increase violent aggressive behaviors.Additionally,Catechol-O-methyltransferase(COMT),the major dopamine metabolism enzyme,is impli-cated in stress responsivity,including aggression.Hence,CT exposure may affect aggression through the effect on the hippocampal function,which might also be modulated by the COMT variations.Objectives:This study examined whether both CT and haplotypes of COMT moderate hippocampal function and thus affect human aggressive behavior.Methods:We obtained bilateral hippocampal functional connectivity maps using resting state functional magnetic resonance imag-ing(MRI)data.COMT haplotype estimation was performed using Haploview 4.2 and PHASE 2.1.Then we constructed a moderated mediation model to study the effect of the CTQ×COMT on aggressive behavior.Results:Three major haplotypes were generated from thirteen single nucleotide polymorphisms(SNPs)within the COMT gene and formed three haplotypes corresponding to high,medium,and low enzymatic activity of COMT.The results showed interactive re-lationships between the Childhood Trauma Questionnaire(CTQ)and COMT with respect to the functional connectivity(FC)of the bilateral hippocampus(HIP)-orbital frontal cortex(OFC).Specifically,CT experience predicted lower negative HIP-OFC coupling in the APS and HPS haplotypes corresponding to the medium and high enzymatic activity of COMT,but greater FC in the LPS haplotypes corresponding to the low enzymatic activity.We also observed a conditional mediation effect of the right HIP-OFC coupling in the link between COMT and aggressive behavior that was moderated by CT experience.Conclusions:These results suggest that CT and COMT have a combined effect on aggressive behavior through hippocampal function.This mediation analysis sheds light on the influence of childhood experience on aggressive behavior in different genetic backgrounds.

Postpartum depression and major depressive disorder:the same or not?Evidence from resting-state functional MRI

Background Although postpartum depression(PPD)and non-peripartum major depressive disorder(MDD)occurring within and outside the postpartum period share many clinical characteristics,whether PPD and MDD are the same or not remains controversial.Methods The current study was devoted to identify the shared and different neural circuits between PPD and MDD by resting-state functionalmagnetic resonance imaging data from 77 participants(22 first-episodic drug-naleMDD,26 drug-nale PPD,and 29 healthy controls(HC)).Results Both the PPD andMDD groups exhibited higher fractional amplitude of low-frequency fluctuation(fALFF)in left temporal pole relative to the HC group;the MDD group showed specifically increased degree centrality in the right cerebellum while PPD showed specifically decreased fALFF in the left supplementary motor area and posterior middle temporal gyrus(pMTG_L),and specifically decreased functional connectivities between pMTG and precuneus and between left subgeneual anterior cingulate cortex(sgACC_L)and right sgACC.Moreover,sgACC and left thalamus showed abnormal regional homogeneity of functional activities between any pair of HC,MDD,and PPD.Conclusions These results provide initial evidence that PPD and MDD have common and distinct neural circuits,which may facilitate understanding the neurophysiological basis and precision treatment for PPD.