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cortex on other regions (Brake et al. 2000). It has been hypothesized however that early stress activates the developing PFC, altering its development and producing precocious maturation but stunted final capacity (Teicher et al. 1996, Teicher et al. 2003).
Working memory
Memory, and especially working memory is vulnerable to stress (Arnsten 1998), which appears to impair performance during tasks that require prefrontal cortex (PFC) operations (Arnsten 2009). Working memory (WM) has been defined as a limited capacity system that provides temporary maintenance and manipulation of information necessary to execute complex tasks (Baddeley 1996, Baddeley 2003). One of these tasks can be the exclusion of unwanted or irrelevant material from consciousness (Brewin, Smart 2005). Meta-analyses (Owen et al. 2005, Rottschy et al. 2012) have shown the involvement of the prefrontal-parietal network (PPN) during working memory processes in healthy participants. Cole et al (2014) suggest a critical role for the frontoparietal control system in promoting and maintaining mental health. They proposed that this system implements feedback control to regulate symptoms and named it the “immune system of the mind”. They noted the frontoparietal control system as an important target for future research. Okon-Singer et al. (2015) described research that demonstrates that stress, anxiety, and other kinds of emotion can profoundly influence key elements of cognition, including selective attention, working memory, and cognitive control. Circuits involved in attention, executive control, and working memory contribute, in turn, to the regulation of emotion.
There is compelling evidence that brain regions and psychological processes commonly associated with cognition, such as the dorsolateral prefrontal cortex and working memory, play a central role in emotion (Okon-Singer et al. 2015). In a recent meta-analysis (Scott et al. 2015) it was suggested that PTSD patients show hypoactivation of regions involved in attention and working memory. In PTSD, several brain imaging studies have demonstrated working memory deficits associated with altered prefrontal activation (Galletly et al. 2001, Clark et al. 2003, Elzinga et al. 2007, Moores et al. 2008, Weber et al. 2005). Patel et al., (2012) described lower activation in dlPFC and lateral parietal cortex in PTSD patients coupled with higher precuneus activation. These authors proposed that the loss of top-down inhibition is one of the
GENERAL INTRODUCTION
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