Sept. 9 (Bloomberg) -- ``Why can't a woman be more like a man?'' Professor Henry Higgins asked in the movie ``My Fair Lady.'' Scientists in Spain may have one answer to the question.

In a report published today in the Proceedings of the National Academy of Sciences, Spanish researchers said that a region of the brain that plays a key role in visual processing and in storing language and personal memories appears to differ between the sexes at the microscopic level.

In their study, the density of connections, or synapses, that transmit messages between neurons in a brain region called the temporal neocortex was greater in men than in women, said neuroscientists at the Cajal Institute, a neurobiology research center in Madrid. One scientist not involved in the report speculated that the smaller number of synapses in the women might actually make those neurons more effective.

``We know that the temporal cortex is involved in language processing, and that women and girls have a slight behavioral advantage in this area,'' said James Booth, a neuroscientist at Northwestern University in Evanston, Illinois. ``In this case `less may be more.' In other words, fewer synapses to other regions may represent increasing specialization of the temporal cortex for language processing in females, and this may be related to their overall better performance on language tasks.''

Booth co-wrote a study published in March that found that certain brain regions involved in language work harder in girls than in boys and that boys and girls activate different parts of their brains when they perform language tasks.

Sexual Variations

Scientists have been studying male and female brains for years, looking for variations that may explain the differences in behavior between the sexes. While men have larger brains and some brain regions are structured or shaped differently, the effect of these differences is not well understood.

The same is true of this newest finding, said Javier DeFelipe, senior author of the new study.

``It's clear that size of brain is not well correlated with any cognitive function and many great artists or Nobel Prize winners have very small brains,'' DeFelipe said in a telephone interview today. ``It's also not better or worse to have greater density.''

DeFelipe and his colleagues used electron microscopes to examine bits of tissue taken from the brains of eight living patients, four men and four women, who had surgery to treat their epilepsy.

Counting Synapses

They took small sections of the temporal neocortex from each patient and methodically counted the number of synapses and neurons in each person, without knowing their gender.

When they finished their calculations and looked to see the sex of the patients, they were astonished, DeFelipe said.

To contact the reporter on this story: Rob Waters in San Francisco at rwaters5@bloomberg.net.

Last Updated: September 9, 2008 00:00 EDT