Word: amygdala
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Dates: during 2000-2009
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...also be that an entirely different part of the brain holds the key to understanding anxiety. Michael Davis, a behavioral neuroscientist at Emory University in Atlanta, has spent six years studying a pea-size knot of neurons located near the amygdala with an impossible name: the bed nucleus of the stria terminalis, or BNST. Rats whose BNST has been injected with stress hormones are much jumpier than those that have got a shot in their amygdala. Could the BNST be at the root of all anxiety disorders? The clues are intriguing, but as scientists are so fond of saying, more...
Owing to an unusual brain disorder, SM046 has a defective amygdala. As a result, her behavior is abnormal in a very particular way. When scientists at the University of Iowa show SM046 pictures of a series of faces, she has no trouble picking out those that are happy, sad or angry. But if the face is displaying fear, she cannot recognize the feeling. She identifies it as a face expressing some intense emotion, but that is all. Her unusual condition strongly suggests that even in Homo sapiens, fear takes hold in the amygdala...
...that way. Rauch's team has spent the past eight years scanning groups of combat veterans, some with post-traumatic stress disorder and some without, to see which areas of the brain light up when they hear tapes recounting their most troubling memories. So far, the signals in the amygdala appear to be more active in those with PTSD than in those without. In addition, signals to the prefrontal cortex of PTSD subjects seem to be weaker than in those without the disorder. Perhaps this explains why the patients still feel threatened even when they are perfectly safe...
...dangerous situations--fire fighters, say, or police officers. Then it may be possible to determine if any changes in their brains are the result of traumatic situations or if the changes predate them. Either is plausible. The stress of surviving a building collapse, for example, could turn a normal amygdala into an overactive one. Or an already overactive amygdala may overwhelm the brain in the wake of a disaster...
...were often very anxious as children. (It's also true that many kids outgrow their anxiety disorders to become perfectly well-adjusted adults.) Is that just a coincidence, as many believe, or does anxiety somehow prime the brain to become depressed later in life? Brain scans show that the amygdala is very active in depressed patients, even when they are sleeping. Studies of twins suggest that many of the same genes could be involved. "There's a lot of overlap," says Dr. Dennis Charney, chief of the research program for mood and anxiety disorders at the NIMH. "Anxiety and depression...