Brain receptor behind learning deficits post-puberty identified

Washington: A novel brain receptor, alpha4-beta-delta, has been labelled as the culprit behind learning deficits that come with puberty.

It is well known that the onset of puberty marks the end of the optimal period for learning language and certain spatial skills, such as computer/video game operation.

In the new study, Dr. Sheryl Smith, professor of physiology and pharmacology, and colleagues at SUNY Downstate Medical Center in Brooklyn showed that alpha4-beta-delta emerges at puberty in the hippocampus, part of the brain that controls learning and memory.

Before puberty, expression of this receptor is low and learning is optimal. However, at puberty, increases in this receptor reduce brain excitability and impair spatial learning.

Smith has shown that the learning deficit could be reversed with the help of a stress steroid that diminishes the harmful effects of the alpha4-beta-delta receptors, thereby facilitating learning.

"These findings suggest that intrinsic brain mechanisms alter learning during adolescence, but that mild stress may be one factor that can reverse this decline in learning proficiency during the teenage years. They also suggest that different strategies for learning and motivation may be helpful in middle school. And it is within the realm of possibility that a drug could be developed that would increase learning ability post-puberty, one that might be especially useful for adolescents with learning disabilities," said Smith.

In 2007, researchers demonstrated that a hormone normally released in response to stress, THP, actually reverses its effect at puberty, when it increases activity of the hippocampus.

While in adults this hormone acts like at tranquilizer, in adolescents it has the opposite effect, an action that may help to explain mood swings in teenagers.

The new report on learning deficits is published in the journal Science.