Word: neural
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Dates: during 2000-2009
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...technique—called two-photon calcium imaging in vivo—was applied to the part of the brain where neural input from the eye is translated into images we see. When the animals, cats, and rats were subjected to visual stimuli of moving black and white stripes, the technique recorded images of hundreds of nerve cells firing simultaneously...
...vitamins, especially for women of childbearing age, and a little bit--100 micrograms a day--goes a long way toward preventing spina bifida and other birth defects. That's why the U.S. government requires that all grain products be fortified with enough folate to stave off these so-called neural-tube defects...
There's good and bad news on folic acid this year. First the good: a March of Dimes poll showed that women of childbearing age are heeding the advice on folic acid. Taking the supplement cuts rates of neural-tube defects like spina bifida as much as 70%, and the poll showed that 40% of women 18 to 45 are taking their daily dose--an all-time high. Perhaps as a result, rates of two major types of neural-tube defects have dropped 25% since...
...good. But what does it mean? Tononi speculates that instead of strengthening neural connections responsible for a given task, as appears to happen during the day or in REM sleep, slow-wave sleep actually indiscriminately weakens the connections among all nerves. The idea sounds counterintuitive, but it may simply be a matter of self-preservation. "Normally the brain takes up 20% of the energy of the entire body," Tononi explains. Most of that energy goes into sustaining the connecting points, or synapses, between neurons. The more you learn, the greater the number of synapses...
Perhaps that's what sleep really is--A series of repeated cycles of pruning and strengthening of neural connections that enables you to learn new tricks without forgetting old ones. Of course, none of that explains why you have to be unconscious for all the pruning and strengthening to occur. Maybe it's just easier to be asleep than awake while the work is going on. "When you fall asleep, it's like you're leaving your house and the workmen come in to renovate," suggests Terry Sejnowski, a computational neurobiologist at the Salk Institute in La Jolla, Calif...