thought to rely on the quality of connections between medial prefrontal and limbic (i.e., amygdala and hippocampal) regions (50). In fact, emerging evidence suggests that cingulum connectivity is inversely associated with the magnitude of fear-potentiated startle response during extinction learning (51). However, the role of hippocampal-prefrontal connectivity has also been highlighted in working memory, contextual memory, and reward learning (52), all of which are functions known to be altered in psychiatric disorders such as PTSD, depression, and schizophrenia. The importance of hippocampal connectivity in PTSD cannot be understated; a burgeoning literature underscores the relevance of abnormal hippocampal-frontal connectivity in this disorder (e.g., Chen & Etkin, 2013). FKBP5 is likely to have an impact on this connectivity, given its role in glucocorticoid signaling. A recent review describes the relevance of glucocorticoids in shaping hippocampal-prefrontal connectivity via dendritic modeling and changing postsynaptic spine plasticity (Hall 2015),
