Psychological stress affects brain function
By Ilene Schneider
Why does your brain seem to fail you just when you need it most? It could be that you are so “stressed out” that your mind freezes at the worst possible time.
At the onset of a stressful situation people sometimes experience a loss of their train of thought, a “zoning out.” Some progress has now been made in understanding the psychological events in the brain that cause the mind to go blank.
A recent article in Scientific American describes research on the impact of stress on the brain.
The prefrontal cortex is called the command center of the brain. The evolutionarily newest part of the brain, it is still developing during adolescence. It contains the neural pathways used in abstract thought and is also a site for the temporary storage of data. Finally, it acts as an inhibitor for harmful behaviors.
Studies suggest that, as a result of genetic inheritance, some people have a lower than average level of the enzymes that restore normal brain activity after stress. There also seems to be a relationship between the experience of stress and loss of prefrontal gray matter.
The dendrites, parts of the nerve cell that communicate with other neurons, can shrink or disappear with stress. While they can reappear, they will not do so if the stress is severe enough.
Under severe stress the prefrontal cortex shifts from sophisticated to basic functions. “Primitive pathways can stop us on a dime or ready us to flee,” say researchers Amy Arnsten. Carolyn Mazure and Rita Sinha, as quoted in Scientific American. These mechanisms may serve a similar function when we face danger in the modern world.”
When stress continues and the prefrontal cortex remains in a primitive posture, normal thinking is stifled. This poses “a devastating handicap in circumstances where we need to engage in complex decision making about a loved one’s serious medical condition or organize an important project to meet a tight deadline,” the researchers concluded.
Not all stress is bad. Brendan Brazier, writing in alive.com distinguishes between uncomplimentary stress – anxiety that produces no benefit – and complementary stress – the right amount of stress to stimulate renewal within the body. Examples of uncomplimentary stress include environmental stress caused by air pollution, on the rise in urban areas especially; nutritional stress, caused by eating unhealthy food; and psychological stress, that which is generally self-imposed from worrying about future events one cannot control, setting unrealistic goals and then failing to meet them and feeling generally unfulfilled, dissatisfied or criticized.
On the other hand, exercise is a form of complimentary stress, stimulating the regeneration of cells and making people look and feel younger. Production stress, that which is generated when someone is trying to achieve a goal, can be healthy in moderation. Brazier calls it “an unavoidable byproduct of a productive life, a necessary part of modern-day success.” Clearly, it is what gets the adrenaline flowing and gets the high achiever across the finish line.