A particular type of neuron behaves differently at different times in a person’s life – which means that younger people absorb more information while older people take in less.
In their study, published in the journal Nature, researchers from Carnegie Mellon University discovered that “inhibitory” neurons behave differently during differently periods of learning.
In younger people, the scientists found, the inhibitory cells served to increase “plasticity,” but in older people the same kind of cells have grown to the point where they actually block learning. In fact, the neurons were only half as active in older people.
Previous researchers were unable to study inhibitory neurons satisfactorily because they did not have the imaging tools to do so. But now newly developed technologies enable researchers to visualize them and explore the neurons’ action at different points in a person’s life span.
"When you're young you haven't experienced much, so your brain needs to be a sponge that soaks up all types of information. It seems that the brain turns off the inhibitory cells in order to allow this to happen," said Sandra J. Kuhlman, assistant professor of biological sciences at Carnegie Mellon. "As adults we've already learned a great number of things, so our brains don't necessarily need to soak up every piece of information. This doesn't mean that adults can't learn, it just means when they learn, their neurons need to behave differently."