"Meaney and colleagues, one of the most cited papers published in the prestigious journal Nature Neuroscience. They had shown previously that offspring of more "attentive" rat mothers (those that frequently nurse, groom, and lick their pups) become adults with lower glucocorticoid levels, less anxiety, better learning, and delayed brain aging. The paper showed that these changes were epigenetic--that mothering style altered the on/off switch in a gene relevant to the brain's stress response."