Posted by: kenwbudd | August 19, 2009

The Brain Is a Co-Conspirator in a Vicious Stress Loop

For the past difficult months you have been exposed to the bleeding edge of our negative economy.

Housing markets spontaneously combust, coworkers quickly disappear and the stifled, tortured moans of diminishing savings and pension plans can be heard through the walls and floorboards,

Now you have the awful sensation that your body’s stress response has taken on a self-replicating and ultimately self-defeating life of its own.

Well, Congratulations! for once you may have it right.

Stress Indicators
It’s bad enough that chronic stress has been shown to raise blood pressure, stiffen arteries, suppress the immune system, heighten the risk of diabetes, depression and Alzheimer’s disease and make one a very unhappy and undesirable companion. Now researchers have discovered that the sensation of being highly stressed can drastically rewire the brain in ways that promote’s a sinister persistence.

Repetitive Disorder
Reporting earlier this summer in the journal Science, Nuno Sousa of the Life and Health Sciences Research Institute at the University of Minho in Portugal and his colleagues described experiments in which chronically stressed rats lost their elastic rat cunning and instead fell back on familiar routines and rote responses, like compulsively pressing a bar for food pellets they had no intention of eating.

Pet Perturbations
Moreover, the rats’ behavioural perturbations were reflected by a pair of complementary changes in their underlying neural circuitry. On the one hand, regions of the brain associated with executive decision-making and goal-directed behaviours had shriveled, while, conversely, brain sectors linked to repeatative habit formation had bloomed.

Cognitively Predisposed
In other words, the rodents were now cognitively predisposed to keep doing the same things over and over, to run laps in the same dead-end rat race rather than seek a pipeline to greener paths or sewers. “Behaviours become very habitual and occur much quicker in stressed animals than in the controls, and what’s worse, the stressed animals can’t shift back to goal-directed behaviours when that would be the better approach,” Dr. Sousa said. “It is a vicious circle.”

Rat In a Rut
Robert Sapolsky, a neurobiologist who studies stress at Stanford University School of Medicine, said, “This is a great model for understanding why stressed people end up in a rut, and then continue to dig themelves deeper and deeper into that rut.”

The truth is, Dr. Sapolsky said, “we’re lousy at recognising when our normal coping mechanisms aren’t working. Our response is usually to do it five times more, instead of thinking, maybe it’s time to try something new.”

Perversity
Perseverance and determination can be an admirable trait and is essential for all success in life, but when taken too far and at the wrong time, it becomes, uncontrollable repetition or simple perversity (?).

“If I were to try to break into the world of modern dance, after the first few rejections the logical response might be, get more practice first,” said Dr. Sapolsky, the author of “Why Zebras Don’t Get Ulcers,” among other books. “but after the 12,000th rejection, maybe I should realise this isn’t a viable career option.”

Reversible
Happily, the stress-induced changes in behaviour and brain appear to be reversible. To rattle the rats to the point where their stress response remained demonstrably hyperactive, the researchers exposed the animals to four weeks of varying degrees of stress: moderate electric shocks, being encaged with dominant rats, prolonged dunks in water.

Those animals who were chronically stressed were then compared with their non-stressed peers. The stressed rats had no trouble learning a task like pressing a bar to get a food pellet or a squirt of sugar water, but they had difficulty deciding when to stop pressing the bar, as normal rats easily did.

Restoration
Fortunately, after some R&R, four weeks’ vacation in a supportive setting, free of bullies and Tasers, the formerly stressed rats looked and behaved just like the controls; able to innovate, discriminate and would stop pressing the bar.

The atrophied synaptic connections in the decisive regions of the prefrontal cortex resprouted, while the overgrown dendritic vines of the habit-prone sensorimotor striatum retreated.

Resilient and Plastic
According to Bruce S. McEwen, head of the neuroendocrinology laboratory at Rockefeller University, the new findings offer a particularly elegant demonstration of a principle that researchers have just begun to grasp. “The brain is a very resilient and plastic organ,” he said. “Dendrites and synapses retract and reform, and reversible remodeling can occur throughout life.”

Neural and Endocrine
Stress may be most readily associated with the nano-second pace of postindustrial society, but the body’s stress response is one of our oldest possessions. Its basic architecture, its linked network of neural and endocrine organs that spit out stimulatory and inhibitory hormones and other factors as needed, looks pretty much the same in us as it does in a goldfish, rat or a frog.

Evading Predators
The stress response is essential for maneuvering through a dynamic world. For evading a predator or chasing down prey, swinging through the trees or fighting off disease. In fulfilling these functions, it is in itself very dynamic and succesful.

As we go about our lives, Dr. McEwen said, the biochemical mediators of the stress response rise and fall, flutter and flare. “Cortisol and adrenaline go up and down,” he said. “Our inflammatory cytokines go up and down.”

Natural Response
The target organs of stress hormones also dance to the same beat: blood pressure climbs and drops, the heart races and slows, the intestines constrict and relax. This system of so-called allostasis, of maintaining control through constant change, stands in contrast to the mechanisms of homeostasis that keep the pH level and oxygen concentration in the blood within a narrow and invariant range.

Balance Restoration
Unfortunately, the dynamism of our stress response makes it vulnerable to disruption, especially when the system is treated too roughly and not according to instructions. In most animals, a serious threat provokes a serious activation of the stimulatory, sympathetic, “fight or flight” side of the stress response but when the danger has passed, the calming parasympathetic circuitry calms everything back down to normal baseline flickering.

Thinking too much
Unfortunately, in humans, the brain thinks too much, extracting phantom threats from every staff meeting or high school dance, and over time the constant hyperactivation of the stress response can unbalance the entire feedback loop.

Health Hazards
Reactions that are desirable in limited, targeted quantities become hazard to your health in promiscuous excess. You need a spike in blood pressure if you’re going to run, to speedily deliver oxygen to your muscles but chronically elevated blood pressure is a source of multiple medical miseries.

Questions
Why should the stressed brain be prone to habit formation? This question remains unaswered but perhaps it is partly to help shunt as many behaviours as possible over to an automatic response mechanism or an ‘auto pilot’. Separating the ‘thinking’ brain from the ‘machine’ and allowing both to do what they are best at.

The thinking half concentrates it’s efforts on solving or dealing with the crisis, whilst the other half keeps the body functioning or simply just cycling a pre-determine routine.

Yet, unless they are ‘dis-connected’, repetitive habits can become entrenched, and as the novelist Ellen Glasgow observed, “The only difference between a rut and a grave are the dimensions.”

Enough is enough! Stop hitting the bar! It’s time to break out of that self destructive cycle. Take the Time to relax, re-appraise your situation and remodel your stressed out brain. It’s the only way forward from where you are. Also, you have a responsibility to look closely at your managers, colleagues and staff for signs of stress and the tell-tale signs of instinctive orprotective, repetative behaviours. If you find it, then try to help them break the viscious circle that their brain has created for them, too.

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