Word: brained
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...series of elegant experiments, Smith and her collaborators showed that this temporary learning deficit could be traced to a remarkable change that occurs at puberty in the hippocampus, a region of the brain that is involved in remembering places and integrating other kinds of learning. The change affects the GABA neurotransmitter system. GABA, which is present in all mammals, inhibits or down-regulates nerve signals, as opposed to exciting them; this calming, relaxing system is activated by tranquilizers like Valium and the popular sleep drug Ambien, which attach to GABA receptors and act similarly to GABA. But at puberty, female...
...until 20 years ago, scientists believed that the human brain was largely mature by puberty. Apparently, they had failed to notice the irrational behavior and flaky thinking of teenagers. Now, of course, we know that the human brain continues to undergo serious restructuring well into the 20s. (See pictures of a diverse group of American teens...
Sophisticated brain-scan studies by Jay Giedd at the National Institute of Mental Health (NIMH) have shown dramatic changes throughout the teenage years as excess gray matter is pruned from the prefrontal cortex - the seat of higher-order thinking and making judgments (like not smoking weed right before your chemistry exam). Meanwhile, behavioral studies have shown what every parent already knows: teens have poor control over impulses and a tendency toward risk taking. Still, relatively little is known about how such changes affect learning or what happens at a biochemical level in the brain as teens go through their addled...
...current issue of Science helps fill in a bit of the picture, drawing evidence from that research-friendly fellow mammal, the mouse. The authors, a team from State University of New York Downstate Medical Center, wanted to look at whether the ability to learn is affected by changes in brain chemistry that occur at puberty. They devised a task that was relatively complex (at least for a mouse) and required learning how to avoid a moving platform that delivered a very mild shock. (See the top 10 animal stories...
...words describing them (happy, angry, sad). The study found that around the onset of puberty (about age 11 for girls and 12 for boys), people take significantly longer to do this easy task. McGivern and his associates attributed the slow pace to the excess number of synapses in the brain at puberty - essentially, too many connections that have yet to be pruned in late adolescence. (See pictures of teens and how they would vote...