Hormone onset in puberty affects learning and may have broad educational and health implications for girls. University of California, Berkeley, researchers examine how puberty hormones might impede some aspects of flexible youthful learning. The researchers find that the onset of puberty hits a ‘switch’ in the brain’s frontal cortex that can reduce flexibility in some forms of learning. In their study of young female mice the researchers discovered significant changes in neural communication in the frontal cortices of female mice after they were exposed to pubertal hormones. The changes occurred in a region of the frontal brain that is associated with learning, attention and behavioral regulation. The study is the first to demonstrate changes in cortical neurotransmission due to hormones at puberty.