Sex helps the brain to grow, say American scientists from Princeton University, reports PLoS One. Researchers conducted a scientific experiment to test whether pleasant but stressful experiences can have the opposite effect. To do this, the scientists left pairs of sexually active rats in cages once a day or once every two weeks and measured the change in the hormonal levels of glucocorticoids, which are supposed to be responsible for the deleterious effect of unpleasant experiences on the brain. The data obtained were compared with those from virgin experimental animals. The results confirmed the expectation that, regardless of the frequency of sexual acts, the sexually active rats had a significant increase in the number of neurons in the hippocampus, a part of the brain associated with memory, whose cells are particularly sensitive to unpleasant experiences. According to the authors of the study, the greater the frequency of sexual acts, the greater the volume of the hypothalamus. Tests conducted on the rodents’ stress level, based on the time it took the animals to start feeding when their environment changed, showed that sexually experienced rats were less anxious than virgins. Blood tests showed that laboratory animals that had sex daily had significantly lower levels of glucocorticoids (stress hormones). Although stress hormones have a detrimental effect on brain tissue, it can be overcome if the experience triggers them. is pleasant, the authors of the study are confident.