Stress: The final frontier (executive functions)


ResearchBlogging.org

It’s visceral. Stress – hits you in the guts. Some of us cope well, some of us don’t – some of our stress lingers, sometimes it’s just the little things, those ‘daily hassles’ that end up tripping the switch. And I don’t think anyone would disagree that chronic pain is an enormous stressor. Regulating that stress level, or managing it effectively, has to be the main challenge in learning to live alongside chronic pain. Today’s post discusses executive functions (the parts of the brain that carry out self regulation) and stress.

Executive function is ‘… a multifaceted construct comprising a number of basic neurocognitive processes, including working memory, cognitive flexibility, response selection, inhibition, initiation, set formation, and set maintenance.’ Williams, Suchy and Rau state that ‘these processes allow us to generate goals and plans, modify our behavior in response to changes in the environment, and follow through and execute necessary actions in order to successfully achieve the intended goals.’ These functions are different from many CNS functions in that they require ‘attention’ or ‘volition’ to initiate and maintain them, whereas many other functions such as those that maintain homeostatis are pretty well automatic.

‘The areas of the brain thought to be primarily responsible for executive functions are the dorsolateral, superomedial, orbitofrontal, and ventromedial prefrontal cortices, anterior cingulate gyrus, the basal ganglia and diencephalic structures, the cerebellum, deep white matter tracks, and some aspects of the parietal lobes – and these are linked to each other and to other structures to ensure most cognitive processes including sensory perception, memory and language are linked.  As a result of these connections, EF serves as the interface between previously acquired knowledge and newly arising information in the environment.’ (Williams, Suchy and Rau, 2009) Can you see why I used a quote? I don’t trust myself to paraphrase!! These structures also link strongly to those automatic/homeostatic areas of the brain, so can influence emotional processing, autonomic control, and appetitive functions.

Even amongst people who don’t have chronic pain (or for that matter, low mood, or a brain injury), we vary in the ways in which we deal with stress. Williams, Suchy and Rau suggest that ‘even slight declines in EF can lead to a breakdown in stress regulation that affects both mental and physical health’ and that ‘aspects of EF are heritable.’ Certain executive functions such as switching attention, inhibiting a response or updating ‘working’ memory have been shown to be inherited.

I won’t go into detail about how this is studied, because it is quite complex and involves drawing conclusions from the results of both trauma or brain injury-induced deficits and the types of pathology found when people have been exposed to significant stress.  It’s also proven to be a very difficult area to study, especially in people with only slight deficits or ‘individual variations’ in the way they respond to stress.  Most neuropsychological tests are fairly blunt instruments and don’t show subtle problems, like those that occur when we’re stressed!

Some interesting findings, however, showing that traits like conscientiousness (also called ‘constraint’) have a positive association with better stress management and better health, while neuroticism (associated with the Behavioural Inhibition System – sensitising us to avoid harm, making us more tuned to negative cues) is associated with greater stress and poorer health.   Extraversion, or the tendency to want interactions with others and to become energised by them can be associated with additional risk taking, but also with positive affect which has a positive effect on health.  Openness to experience is a trait where people are basically inquisitive (that’s me to a T!) is associated with better adaptation to chronic illness, and the last one is agreeableness, or getting along with others and to cooperate, and it is associated with better health and lower stress.

What does this mean for chronic pain and executive functions or self regulation?

Perhaps some of the vulnerability to having trouble coping with longterm pain arises from genetic tendencies in the way our executive functions operate.  Remember that chronic pain is a stressor, and that chronic pain problems can arise during periods of increased exposure to stress.  This suggests that the effect of chronic pain on executive functions, or the ability to self regulate might influence how efficiently we can cope.  It also suggests that if our self regulation skills are vulnerable, then under stress we may find it much more difficult to manage.

From my last post, it also seems that we can develop self regulation, provided we have sufficient resource in terms of energy and social support (and someone to help establish appropriate goals).  Some people may find it more challenging not because they have less inclination to cope, but simply because they have certain tendencies that are inherited to make this aspect of coping much more difficult.

If as clinicians we can identify those people who need more support, and especially if we can identify some of the ‘components’ of executive functioning such as sensitivity to activating the Behavioural Inhibition System, maybe we can help prevent some of the chronic disability arising from having chronic pain, even if we can’t prevent the pain from being present. After all, it’s not the pain itself that is problematic – it’s the disability or functional limitations arising from the pain that create problems.

Williams, P., Suchy, Y., & Rau, H. (2009). Individual Differences in Executive Functioning: Implications for Stress Regulation Annals of Behavioral Medicine, 37 (2), 126-140 DOI: 10.1007/s12160-009-9100-0

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