Stress-induced alterations in prefrontal dendritic spines: Implications for post-traumatic stress disorder

The medial prefrontal cortex (mPFC) is involved in a variety of important functions including emotional regulation, HPA axis regulation, and working memory. It also demonstrates remarkable plasticity in an experience-dependent manner. There is extensive evidence that stressful experiences can produce profound changes in the morphology of neurons within mPFC with a variety of behavioral consequences. The deleterious behavioral outcomes associated with mPFC dysfunction have been implicated in multiple psychopathologies, including post-traumatic stress disorder (PTSD). Given the prevalence of these disorders, a deeper understanding of the cellular mechanisms underlying stress-induced morphological changes in mPFC is critical, and could lead to improved therapeutic treatments. Here we give a brief review of recent studies examining the mechanisms underlying changes in mPFC pyramidal neuron dendritic spines - the primary sites of excitatory input in cortical pyramidal neurons. We begin with an overview of the effects of chronic stress on mPFC dendritic spine density and morphology followed by proposed mechanisms for these changes. We then discuss the time course of stress effects on mPFC as well as potential intercellular influences. Given that many psychopathologies, including PTSD, have different prevalence rates among men and women, we end with a discussion of the sex differences that have been observed in morphological changes in mPFC. Future directions and implications for PTSD are discussed throughout.