Episodic memory after trauma exposure: Medial temporal lobe function is positively related to re-experiencing and inversely related to negative affect symptoms

• Type of Material: Article
• Authors: Jennifer Stevens, Emory University; Renuka Reddy, Emory University; Ye Ji Kim, Emory University; Sanne J. H. van Rooij, Emory University; Timothy D. Ely, Emory University; Stephan Hamann, Emory University; Kerry Ressler, Emory University; Tanja Jovanovic, Emory University
• Language: English
• Date: 2018-01-01
• Publisher: Elsevier: Creative Commons
• Publication Version: Final Published Version
• Copyright Statement: © 2017 The Authors
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.nicl.2017.11.016
• Title of Journal or Parent Work: NeuroImage: Clinical
• ISSN: 2213-1582
• Volume: 17
• Start Page: 650
• End Page: 658
• Grant/Funding Information: This work was primarily supported by the National Institutes of Mental Health (F32 MH101976 to J.S.S., MH071537 to K.J.R., and MH098212 to T.J.).; Support was also received from Emory and Grady Memorial Hospital General Clinical Research Center UL1TR002378, NIH National Centers for Research Resources (M01RR00039), National Center for Advancing Translational Sciences of the NIH (UL1TR000454).
• Keywords: Episodic memory; Hippocampus; Trauma; Ptsd; Symptom dimensions; Amygdala
• Research Categories: Biology, Neuroscience; Psychology, General

Abstract

Hippocampal structure is particularly sensitive to trauma and other stressors. However, previous findings linking hippocampal function with trauma-related psychopathology have been mixed. Heterogeneity in psychological responses to trauma has not been considered with respect to hippocampal function and may contribute to mixed findings. To address these issues, we examined associations between data-driven symptom dimensions and episodic memory formation, a key function of the hippocampus, in a trauma-exposed sample. Symptom dimensions were defined using principal components analysis (PCA) in 3881 trauma-exposed African-American women recruited from primary care waiting rooms of a large urban hospital. Hippocampal and amygdala function were subsequently investigated in an fMRI study of episodic memory formation in a subset of 54 women. Participants viewed scenes with neutral, negative, and positive content during fMRI, and completed a delayed cued recall task. PCA analysis produced five symptom dimensions interpreted as reflecting negative affect, somatic symptoms, re-experiencing, hyper-arousal, and numbing. Re-experiencing was the only symptom type associated with hippocampal function, predicting increased memory encoding-related activation in the hippocampus as well as the amygdala. In contrast, the negative affect component predicted lower amygdala activation for subsequently recalled scenes, and lower functional coupling with other important memory-related regions including the precuneus, inferior frontal gyrus, and occipital cortex. Symptom dimensions were not related to hippocampal volume. The fMRI findings for re-experiencing versus negative affect parallel differences in behavioral memory phenomena in PTSD versus MDD, and highlight a need for more complex models of trauma-related pathology.