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Forget the heart, lasting love is all in the head
(China Daily)
Updated: 2005-12-07 06:06
It may be better to have loved and lost than never to have loved at all, but
why is it so hard to find again? It may be that our brains are fixated on our
former lovers, according to scientists.
Researchers at Florida State University examined the nature of love by
studying the brains and behaviour of male prairie voles a type of rodent picked
for their habit of lifelong monogamy and aggression towards other females once
they have found a mate.
The scientists found that
males became devoted to females only after they had mated. The bond coincided
with a huge release of the feel-good chemical dopamine inside their brains.
Brandon Aragona, who led the study, demonstrated that dopamine was the voles'
love drug by injecting the chemical into the brains of males who had not yet had
sex with female companions.
Immediately, they lost interest in other females and spent all of their time
with their chosen one.
Further experiments showed that dopamine restructured a part of the vole's
brain called the nucleus accumbens, a region that many animals have, including
humans.
The change was so drastic that when paired-up males were introduced to new
females, although their brains still produced dopamine on sight, the chemical
was channelled into a different neural circuit that made them go cold towards
the new female.
"It seems that the first time they get together and the bond forms, it locks
them into that monogamous behaviour ... You can take a female away from a male
once he's formed a bond with her and two weeks later put him with a different
female and he won't be remotely interested," said Aragona, whose study appears
in the journal Nature Neuroscience.
The researchers said that while the love lives of voles differ from those of
humans, the same brain structures work in much the same ways across different
species.
"Things are always going to be more complicated in humans because we have
larger brains and are under different pressures, but the basic mechanisms are
there," said Aragona.
The Guardian
(China Daily 12/07/2005 page1)
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