Poster F57, Tuesday, March 27, 8:00-10:00 am, Exhibit Hall C
Traumatic stress does not exert lesion-like effects on hippocampal function in children
Jennifer Stevens1, Sanne van Rooij1, Ye Ji Kim1, Timothy Ely1, L. Alexander Vance1, Bekh Bradley1,2, Tanja Jovanovic1; 1Emory University School of Medicine, 2Atlanta Veterans' Affairs Medical Center
Non-human animal findings indicate the hippocampus is highly sensitive to the damaging effects of stress, but little previous research has addressed effects of early life stress on human hippocampal function. Here we investigated the effects of trauma exposure on fMRI activation in a hippocampus-dependent episodic memory encoding task, in school-age children at risk for experiencing high levels of inner-city violence. N=50 children ages 8-14 participated; this age window targets a time of peak exposure to childhood trauma, as well as substantial maturational change in medial temporal lobe connections with the prefrontal cortex. During fMRI, children viewed static scene stimuli with emotional content of negative, positive, or neutral valence. After a 30-minute delay, children completed a cued recall task assessing their memory for each scene from the scanning session. Children showed greater memory for negative and positive scenes, relative to neutral (ps<.05). Age was positively associated with overall recall performance (R2=.07, p<.05) and the enhancing effect of emotion on recall (negative–neutral scene recall; R2=.08, p<.05). Trauma load (number of different types of traumas experienced; TESI-C) was positively associated with recall performance, particularly for negative scenes (all scenes: R2=.14, negative scenes: R2=.25, p<.05). Furthermore, trauma exposure was positively associated with encoding-related activation in the hippocampus (R2=.25, p<.05) and amygdala (R2=.11, p<.05) for negative stimuli. Findings point to a surprising increase in hippocampal activity with greater childhood trauma load, particularly for negative stimuli. We posit that this may represent a neurodevelopmental adaptation to a high-trauma environment, facilitating memory for negative environmental cues.
Topic Area: LONG-TERM MEMORY: Development & aging