Word: brained
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Dates: during 2000-2009
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...exhale slowly. You're probably not aware of it, but your heart has just slowed down a bit. Not to worry; it will speed up again when you inhale. This regular-irregular beat is a sign of a healthy interaction between heart and head. Each time you exhale, your brain sends a signal down the vagus nerve to slow the cardiac muscle. With each inhale, the signal gets weaker and your heart revs up. Inhale, beat faster. Exhale, beat slower. It's an ancient rhythm that helps your heart last a lifetime. And it leads to lesson...
...YEARS PSYCHOLOGISTS HAVE concentrated on the behavioral symptoms of burnout: lost energy, lost enthusiasm and lost confidence. Now, thanks to new brain scans and more sophisticated blood tests, scientists can directly measure some of the effects of stress on mind and body--often with surprising results...
Because cortisol is a long-acting hormone, you can dally under the covers a bit without losing any steam. But your brain is already taking steps to protect you from the shock of starting a new day. Rising cortisol levels signal the hypothalamus to stop sounding the alarm. Other parts of the brain chime in, and eventually the adrenal glands ratchet down their cortisol production. In other words, the brain's stress response contains its own off switch...
More recently, researchers have found that subjects with low self-esteem are more vulnerable to stress. Jens Pruessner at McGill University in Montreal believes that the hippocampus, a finger-size structure located deep in the brain, is at least partially responsible. It turns out that the hippocampus, which helps you form new memories and retrieve old ones, is particularly sensitive to the amount of cortisol flooding your cerebrum. So when cortisol levels begin to rise, the hippocampus sends a set of signals that help shut down the cortisol cascade...
Using several different types of brain scans, Pruessner has shown that people who test below average on self-esteem also tend to have smaller-than-average hippocampi. The differences become clear only when you compare groups of people, Pruessner notes, so you can't look at any single person's brain scan and determine whether he or she has low self-esteem. But when you look at overall results, they suggest that a smaller hippocampus simply has more trouble persuading the rest of the brain to turn off the stress response...