Sex apparently can
help the brain grow, according to new findings in rats.

Sexually active
rodents also seemed less anxious than virgins, Princeton scientists discovered.

Past findings had
shown that stressful, unpleasant events could stifle brain
cell growth in adults. To see if pleasant albeit stressful experiences
could have the opposite effect, researchers studied the effects of sex
in rats.

Scientists played
matchmaker by giving adult male rats access to sexually receptive females
either once daily for two weeks or just once in two weeks. They also measured
blood levels of stress hormones known as glucocorticoids, which researchers
suspected might lie behind the detrimental effects that unpleasant experiences
have on the
brain.

When compared with
male virgins, both groups of sexually active rats had cell proliferation, or an
increase in the number of neurons, in the hippocampus, a part of the brain
linked with memory whose
cells are especially sensitive to unpleasant experiences. The rats that had
more sex also had adult brain cells grow, as well as a rise in the number of
connections between brain cells.

However, the rodents
that only saw females once in two weeks had elevated levels of stress hormones,
while the rats that had regular access showed no increase in the hormones.
Sexually experienced rodents also proved less anxious than virgins, in that
they were quicker to chomp down on food in unfamiliar environs.

These findings
suggest that while stress hormones can be detrimental to the brain, these
effects can be overridden if whatever experiences triggered them were pleasant.

The scientists
detailed their findings online July 14 in the journal PLoS ONE.

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