The toss, Mateo said, "scares the bejesus" out of squirrels, which then usually "run for cover." During her tests, however, only the squirrels with moderately elevated cortisol levels figured out the maze and swiftly escaped the Frisbee. Rodents with too little or too much cortisol had trouble learning. The findings have been accepted for publication in the journal Neurobiology of Learning and Memory. Prior research suggests the same thing happens to humans, though the challenges may be somewhat different. For example, a student who crams the night before a test and has a temporary boost in cortisol may benefit, but too little energy to the brain or too much can lead to poor concentration in the critical moment. When we get older, the entire system can go out of whack. Mateo explained that the brain winds up telling the adrenal gland to release cortisol, but the shut off-signal may become weaker as people age. As a result, "the brain swims in cortisol, but over time has fewer receptors for it and, surprise surprise, we have cognitive deficits." Such elevated levels have been linked to Alzheimer's disease. Research on stress in rats suggests possible treatments might focus on "an executive hub" at the front of the brain that quells the whole alarm process, which is centered deeper in the brain. Steven Maier, a University of Colorado researcher, chemically inactivated this hub in the brainstem of rats, which then showed signs of depression and anxiety associated with uncontrolled stress levels. But what about stress management? "If an organism can cope behaviorally with an event, there's no need for intense physiological adaptation," Maier said. [an error occurred while processing this directive]Related Links: [an error occurred while processing this directive] |
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