Can traumatic stress alter the brain? Understanding the implications of early trauma on brain development and learning.

BACKGROUND Youth who experience traumatic stress and develop post-traumatic symptoms secrete higher levels of the glucocorticoid cortisol than youth with no trauma history. Animal research suggests that excess corticosterone secretion can lead to neurotoxicity in areas of the brain rich in glucocorticoid receptors such as the hippocampus and the prefrontal cortex (PFC). These two areas of the brain are involved in memory processing and executive function, both critical functions of learning. METHODS In this article, we summarize findings presented at the National Summit for Stress and the Brain conducted at Johns Hopkins University's Department of Public Health in April 2011. The presentation highlighted structural and functional imaging findings in the hippocampus and PFC of youth with post-traumatic stress symptoms (PTSS). RESULTS Youth with PTSS have higher levels of cortisol. Prebedtime cortisol levels predict decreases in hippocampal volume longitudinally. Cortisol levels are negatively correlated with volume in the PFC. Functional imaging studies demonstrate reduced hippocampal and PFC activities on tasks of memory and executive function in youth with PTSS when compared with control subjects. CONCLUSIONS Effective interventions for youth with PTSS should target improved function of frontolimbic networks. Treatment outcome research using these potential markers can help develop more focused interventions that target the impaired learning of vulnerable youth experiencing traumatic stress.