Research Points in Attention Given Babies : Answer to Aging Woe May Be in Infancy
A little excitement in infancy can lead to a sharper mind and clearer thinking in old age, according to a group of researchers studying the effects of aging on the brains of laboratory rats.
Robert M. Sapolsky, a Stanford University researcher, said he and a group of Canadian scientists found that giving just minimal handling to infant rats imprinted a hormonal response that led eventually to a smaller loss of learning ability and memory when the rats reached old age.
“This is currently a rat story, and it’s not clear if this is a human story, but that is what we’re working on,” Sapolsky said.
One Group Handled
He said the scientists conducted the experiment using two groups of infant rats. One group was taken from their cages and placed in a bed of wood shavings for a brief time. The other group was left in their cages and received no handling.
Later, the two groups were put through a maze to test their ability to think and learn.
After 2 1/2 years, Sapolsky said, the tests showed that the rats that had received the additional stimulation of being handled early in life were clearly able to think and learn more quickly than the rats that were not handled.
Sapolsky said the experiment indicated that the mere act of adding sensory stimulation to the lives of the rats at a very early age enabled them to more efficiently handle stress throughout their lives. And by coping more efficiently with stress, the rats secrete less of a class of hormones called glucocorticoids. He said these hormones are known to cause the loss of brain cells that are critical in the thought processes.
“Lots of these hormones and lots of stress will accelerate neuron death in the brain,” he said. “And this happens in a part of the brain that has a lot to do with learning and memory. It will accelerate some of the learning deficits (associated with aging).”
Sapolsky said the simple act of handling the rats seems to determine forever just how the rats respond to stress.
“It turns out that what handling (of the rats) does is make a very, very sharp, well-defined brake (on the stress response),” he said. “As a result of the brake working better,” the rat throughout its life secretes less brain-damaging hormone.
Fewer Neurons Killed
Sapolsky said autopsies of the rats showed that the handled rats had fewer killed neurons than the rats that had not been handled. And the only difference in their life, he said, had been that brief period of additional attention during infancy.
He said it is not clear if the response of the rats provides a model for a similar phenomenon in humans or if this finding will have any application in better understanding senility or Alzheimer’s disease, both of which cause learning deficits in aged humans.
“At the moment, we don’t know,” he said. “But we’re working very hard on that.”
