Early on, they took a trip to the zoo, where the toddler had a traumatic experience: A goose ran at the little girl, scaring her. And the fact that it happens at such high rates in small children might explain why so many of their memories seem to disappear.įrankland has worked on neurogenesis for the past five years, and he's also watched his daughter age from 2 to 7. "We're convinced that neurogenesis is one of the major factors that leads to forgetting in both adults and infants," says Frankland. But when they were given drugs that reduced the new connections in the brain, the baby animals retained the memories at a much higher rate. As expected, the baby animals lost the memories. Frankland and his colleagues trained baby and adult animals in memory tasks, like learning to fear an area where they received small shocks, and tested them a few weeks later. This work led Frankland to look at infancy, when neurogenesis happens at much higher rates than adulthood (a human infant's brain generates 2,100 to 2,800 new neurons each day compared with about 700 for adults). Frankland explains it this way: If a system suddenly adds a bunch of new connections and complexity, the entire setup may go sideways for a while until things are sorted out. The researchers found that the animals forgot the experience quickly: Neurogenesis caused rats to lose memories faster. To do that, they gave animals drugs that made their brains create new neurons, then tested their ability to remember a bit of training. Frankland and his lab collaborators wanted to find out how new neuron production in the brain-neurogenesis-affects memories already stored in the hippocampus. Paul Frankland, a researcher at the Hospital for Sick Children in Toronto, knew that in order for a memory to be planted in our brains for good, it first needs to get stored in the hippocampus-which connects related simultaneous memories from different sensory regions of the brain, forming them into a single episode. As kids' brains develop and add connections, they lose more memories than they create-and at the same time, early memories tend to be partial and therefore more likely to erode. People have been aware of this sort of childhood amnesia at least since Sigmund Freud coined the phrase at the turn of the 20th century, but it's only recently that advanced imaging has been combined with long-term behavioral studies to allow scientists to start to really understand how childhood memory fundamentally differs from the adult version. "Something was happening at age 7," says Bauer. They found that the children remembered about 60 percent of the events during their second interview (when they were about 5) but much, much less in the third (when they were around 8)-a deterioration of memory greater than usual. Both times, they asked the kids to recall events they described as 3-year-olds. The researchers then brought back some of the children two years later and again six years later. That's backed up by research: In one major study, Emory University psychologist Patricia Bauer and a colleague invited a bunch of 3-year-olds into her lab and interviewed the children about events in the previous three months, like trips to the zoo or birthday parties. But ask him about the same trip when he's 7, and it's likely he won't remember a thing. Ask a 5-year-old about his visit to the aquarium a year prior, and there's a good chance he'll tell you all sorts of details: the color of the reef, what was in the touch tank. A weird thing happens to kids around kindergarten.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |