Brain size matters for sex
The fear centre finds a role in
arousal.
21 January 2004
HELEN
PEARSON
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| The amygdala (light
blue) is involved in emotional responses. |
| © SPL |
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Researchers have suggested that size matters when it
comes to sex - the size of part of the brain, that is1.
According to David Reutens at the University of Melbourne,
Australia, a person's sex drive may be proportional
to the size of their amygdala, a small 'emotion' centre
nestled at the base of the brain.
The almond-sized nugget has been implicated in sex
drive before; it is tickled by erotic movies and is
vital for mating behaviour in many animals. But the
effect of its size was unclear.
Reutens and colleagues scanned the brains of 45 patients
with chronic epilepsy, a condition that typically dampens
sex drive. As part of their treatment, they had undergone
surgery to remove part of their brain, which freed up
the remaining areas to run more normally.
Through interviews and questionnaires, the team found
that patients with the greater amount of amygdala left
intact after surgery had a larger sex drive.
Researchers must now test whether this holds true in
the general population by comparing amygdala size and
sexuality in a large group, says Jim Pfaus, who studies
sexual behaviour at Concordia University in Montreal,
Canada. If it does, "they've discovered something quite
extraordinary", he says.
Huge market
Scientists traditionally think of the amygdala as the
part of the brain that processes reactions to fear.
But some researchers think it may help us to focus our
attention on any emotional cues - be they fearful or
provocative. Hence, a larger amygdala might boost the
likelihood of a sexual trigger leading to arousal, Reutens
suggests.
The amygdala is unlikely to account for sex drive on
its own, Pfaus adds. It is intimately linked to other
brain regions, including the hypothalamus, which sets
off physical responses to arousal, such as erections.
If researchers can nail down the roots of sex drive,
they might ultimately hit on drugs that compensate for
lack of arousal. Based on the runaway success of the
anti-impotence drug Viagra, researchers believe this
is a potentially huge pharmaceutical market.
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