A new study in mice suggests that a mother's childhood experiences may affect the brain function of her offspring. Researchers found that mouse moms who were physically active, stimulated and changed their living arrangements frequently as youngsters gave birth to babies with better memory than those born to mothers raised in dull environments.
"How well mice remember when they are young is influenced by exposures to stimuli of their mothers when they were young," says Larry Feig, a biochemist at Tufts University Medical School in Boston and senior author of the study that will published tomorrow in The Journal of Neuroscience.
This study adds to an accumulating body of evidence that not all the physiological characteristics passed from parents to offspring are genetic, Feig notes. Is it possible the same is true in humans? "The best we could say is if this occurs in humans," he says, "it would suggest that experiences [your mother] had during adolescence could influence your memory."
Feig's team previously showed that stimulating environments trigger a biochemical cascade in mice that enhances their recall by fostering communication between nerve cells in the hippocampus, a region of the brain that controls memories.
In this study, the researchers were trying to determine whether mothers and fathers could pass along this enhanced memory to their offspring.
Feig says that he and his colleagues split several hundred pre-adolescent (15-day-old) mice, genetically engineered to have poor memories, into two groups: Half spent their "adolescence" (two weeks) living the good life in large cages with about a dozen other mice and filled with plastic tubes, toys, cardboard boxes, and running wheels. The researchers regularly re-arranged the toys in their cages and placed novel objects in them. The other group of mice, meanwhile, was put in sparse, small cages with fewer companions and nothing but a bed of pine chips. There were no toys or treadmills – and nothing was rearranged during their stay.
When the mice reached sexual maturity (two months later), the researchers allowed them to mate and then studied the brain activity of their offspring. The offspring of mice housed in the exciting digs performed better than their peers in the small, boring quarters on memory tests and showed enhanced brain activity.
In fact, Feig says, the offspring of the stimulated moms had such good memories that they performed as well as mice that did not carry the engineered genetic defect. Unfortunately, he said, their sharp recall faded after around three months and their kids did not appear to benefit.
Oh, and dads – no offense, but the researchers found that fathers' upbringing apparently plays no role in the memory abilities of their young.