|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
|
Details: Summer
2003 Her hormone levels take a nosedive, her hair falls out in clumps, and if she had keys (and a destination), she'd probably forget them. But for an old female mouse, physiology doesn't have to be destiny, says Karyn Frick, assistant professor of psychology. "In our lab, you can see elderly females performing just as well as young mice on certain memory tasks," says Frick. And what the psychologist has learned may be good news for members of our own species -- off both sexes. For the past few years, Frick has been investigating the effects of estrogen enhancement on what's known as spatial memory, the ability to remember objects and locations. "Spatial memory is essential for finding your way, but it's often impaired in the elderly," she explains.
The culprit appears to be a part of the brain called the hippocampus, a region responsible for the short-term storage and integration of information. For reasons that remain unclear, hippocampal function declines with age. The downward slope becomes particularly noticeable after female mice undergo the rodent equivalent of menopause and their estrogen levels decline. In earlier studies, Frick discovered that providing supplemental estrogen resulted in "robust improvement" in tasks such as locating and comparing objects and navigating a water maze, all of which required a working spatial memory system. But recent reports about the ill effects of hormone replacement therapy in women -- to say nothing of whether it's good for men to get more in touch with their female side -- have made estrogen a less-attractive memory-enhancement strategy for humans. Fortunately, Frick has found a promising alternative. "We give the elderly female mice lots of toys and access to running wheels and let them play three hours a day for several weeks," she says. "The animals have a fantastic time, and after this period of 'enrichment,' we see a dramatic improvement in their memories." Moreover, their hippocampi show increased levels of synaptophysin, a protein associated with memory. This is Frick's most significant finding, and one that may point to the physiology of memory loss. Frick and co-author Stephanie M. Fernandez report their results in the July issue of the journal Neurobiology of Aging. The study dealt with females because Frick already had them in her lab for her estrogen research (and also because, as she points out, most studies are performed on male rodents). But she thinks it likely that the effect would work in male mice as well. What about humans? "Remaining mentally and physically active should help protect us against the normal memory declines of aging," says Frick. The psychologist believes
that her job probably provides the requisite amount of cognitive
stimulation. As for the physical, outfitting her office with a running
wheel is still under consideration. |
 |
||
|
||
|
|
Yale
Alumni Magazine, PO Box 1905, New Haven, CT 06509-1905. USA.
|