, 2012). Animal studies have shown that PKCα signaling is increased in the PFC in response to an acute stress, where it weakens PFC function (Birnbaum et al., 2004) and drives stress-induced loss of PFC gray matter (Hains et al., 2009). In contrast, PKC signaling strengthens amygdala function (Bonini et al., 2005). Thus,

the link to risk of PTSD is particularly intriguing. Another important risk factor for PTSD and depression 3-MA molecular weight appears to be sex, and specifically the presence of estrogen, as females of cycling age are at greater risk for illness than noncyling women/girls or men (Breslau et al., 1999 and Weissman et al., 1991). Studies in animals suggest that some of this increased risk may be due to estrogen’s effects on catecholamines and on spine morphology in medial PFC neurons. Animal studies have shown that estrogen promotes catecholamine production, including more DA in the dlPFC (Kritzer and Kohama, 1998). In rodents, estrogen exaggerates stress-induced dendritic changes in medial PFC neurons that drive the amygdala and increase the stress response (Shansky et al., 2009). In humans, sex appears to interact with COMT

genotype in influencing emotional responsivity (Chen et al., 2011), and there are likely numerous other biological and nonbiological (e.g. cultural) factors that contribute as well. For example, perceived control over a stressor is a key factor in alleviating

stress-induced PFC dysfunction (Bland CP-690550 mouse et al., 2003), and women traditionally have less control over their lives than men. In the face of uncontrollable trauma, treatment may be needed to restore PFC function and allow the person to better help themselves. The data discussed so far indicate that an important goal for treatment of PTSD should be to strengthen PFC regulation, allowing the patient to better regulate Adenosine their emotions, thoughts and actions. In other words, the animal data suggest that a stronger PFC should help patients to extinguish fear responses (via PFC regulation of amygdala), to calm themselves and reduce hyperarousal (e.g. via PFC regulation of brainstem), and reduce flashbacks and intrusive memories (via PFC regulation of posterior cortex and hippocampus). It is likely that many behavioral therapies act at least in part by strengthening PFC. For example, exposure therapy may work in part by creating a safe context where the PFC can increasingly come “on-line” to regulate the amygdala, breaking the vicious cycle of primitive brain responses and extinguishing the traumatic response. However, many patients are stuck in a vicious cycle where the PFC remains dysfunctional and primitive circuits dominate, and for these patients, medication may be essential to normalize brain physiology and allow the return to health.