Word: cortexes
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Dates: during 1990-1999
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...latest Nature Neuroscience, Dr. Antonio Damasio and his colleagues describe two young adults--a woman, 20, and a man, 23--who suffered early injuries to the prefrontal cortex, an area of the brain thought to serve as a kind of moral and social compass. The woman was run over by a car at 15 months; the man had a brain tumor removed at three months. Both made remarkable recoveries until they began to display serious behavioral problems...
Damasio knows that adults with injuries to the prefrontal cortex develop very similar problems, often quitting their jobs, gambling away their savings and alienating family and friends. But in those cases, the people still seem to know the difference between right and wrong. By contrast, the two young adults never seemed to have developed a moral compass in the first place...
FERTILE MINDS Turning conventional thinking on its head, scientists have shown that new brain cells continue to be generated in the cerebral cortex of an adult brain. Alas, the adult was a macaque monkey. Still, the finding marks the first time that new neurons--thousands of them a day--have been seen in the cerebral cortex, the most advanced region of the brain, responsible for reasoning, decision making and memory. The implication: if brain cells grow as we age, the discovery may one day lead to treatments for degenerative brain disorders like Alzheimer's disease...
...diseases, while damaging the hippocampus, leave core consciousness unimpaired. That's because it evolved much earlier than extended consciousness, Damasio says, and thus is dependent on more ancient structures, especially those located within the brain stem and hypothalamus. Among the most important: a large region called the cingulate cortex, which not only receives sensory input from the skin, muscles and internal organs but also sends out signals to initiate movement and focus attention, as when emotions send our blood pressure soaring or make our hair stand...
...demonstration of the cingulate cortex's importance to consciousness, Damasio recalls a patient he calls L. After a comparatively minor stroke, she became bedridden, lying utterly still and mute for six months even though her physical condition seemed to suggest she could have resumed her daily life. During her ordeal, she later told Damasio, she felt absolutely no desire to speak or move. "Her mind," he says, "had not been imprisoned in the jail of her immobility. Instead it appeared that there had not been much mind at all, and nothing that would resemble consciousness." It turned out that...