Washington, Jan 22: Researchers have recently suggested that the size of the brain matters when it comes to engaging in sex. According to David Reutens at the University of Melbourne, 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 earlier been implicated in sex drive, which gets tickled by erotic movies and is vital for mating behaviour in many animals. But the effect of its size was unclear.

Therefore, 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 added.