How Brain Habits can Hijack the Stress Loop (good article)

note: this is interesting confirmation of the Taoist emphasis on operating from the belly or heart centers, rather than the head. But also reveals how plastic the brain is, and that its bad habits can be re-wired. Nothing new here really, but useful info for teachers and for understanding that the hard science matches the energetic science.
michael

BRAIN IS A CO-CONSPIRATOR IN A VICIOUS STRESS LOOP
By Natalie Angier
New York Times
August 18, 2009

If after a few months’ exposure to our David Lynch economy, in which housing
markets spontaneously combust, coworkers mysteriously disappear and the
stifled moans of dying 401(k) plans can be heard through the floorboards,
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,
congratulations. You are very perceptive. It has.

As though it weren’t 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
undesirable dinner companion, now researchers have discovered that the
sensation of being highly stressed can rewire the brain in ways that promote
its sinister persistence.

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.

Moreover, the rats’ behavioral 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 behaviors had shriveled, while, conversely, brain sectors
linked to habit formation had bloomed.

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-ended rat race
rather than seek a pipeline to greener sewers. “Behaviors become habitual
faster in stressed animals than in the controls, and worse, the stressed
animals can’t shift back to goal-directed behaviors when that would be the
better approach,” Dr. Sousa said. “I call this a vicious circle.”

Robert Sapolsky, a neurobiologist who studies stress at Stanford University
School of Medicine, said, “This is a great model for understanding why we
end up in a rut, and then dig ourselves deeper and deeper into that rut.”

The truth is, Dr. Sapolsky said, “we’re lousy at recognizing 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.”

And though perseverance can be an admirable trait and is essential for all
success in life, when taken too far it becomes perseveration —
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, practice even more,” said Dr. Sapolsky, the
author of “Why Zebras Don’t Get Ulcers,” among other books. “But after the
12,000th rejection, maybe I should realize this isn’t a viable career
option.”

Happily, the stress-induced changes in behavior 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 stressors: moderate electric shocks, being encaged
with dominant rats, prolonged dunks in water. Those chronically stressed
animals were then compared with nonstressed 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.

But with only four weeks’ vacation in a supportive setting free of bullies
and Tasers, the formerly stressed rats looked just like the controls, able
to innovate, discriminate and lay off the bar. Atrophied synaptic
connections in the decisive regions of the prefrontal cortex resprouted,
while the overgrown dendritic vines of the habit-prone sensorimotor striatum
retreated.

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.”

Stress may be most readily associated with the attosecond 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 a goldfish or a red-spotted
newt as it does in us.

The stress response is essential for maneuvering through a dynamic world —
for dodging a predator or chasing down prey, swinging through the trees or
fighting off disease — and it is itself dynamic. As we go about our days,
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.”

The target organs of stress hormones likewise dance to the 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.

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 tamps everything back down to baseline flickering.

In humans, though, the brain can think 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. Reactions that are desirable in limited, targeted quantities become
hazardous 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.

Why should the stressed brain be prone to habit formation? Perhaps to help
shunt as many behaviors as possible over to automatic pilot, the better to
focus on the crisis at hand. Yet habits can become ruts, and as the novelist
Ellen Glasgow observed, “The only difference between a rut and a grave are
the dimensions.”

It’s still August. Time to relax, rewind and remodel the brain.