Research by Yale scientists shows that males and females have essentially unisex brains - at least in flies - according to a recent report in Cell designed to identify factors that are responsible for sex differences in behavior.
The researchers showed that a courting "song and dance" routine that only male flies naturally perform - one wing is lifted and wiggled to make a humming "song" - can also be triggered in female flies by artificially stimulating particular brain cells that are present in both sexes. It isn't what you've got - it's how you use it, the authors say.
"It appears there is a largely bisexual or 'unisex brain.' Anatomically, the differences are subtle and a few critical switches make the difference between male and female behavior," said senior author Gero Miesenboeck, formerly of Yale University and now at the University of Oxford.
According to the authors, most male animals have to perform elaborate courtship displays to try to convince the female that they are worthy mates. Their study was designed to see what neurons were responsible for behavior in the courtship dance of flies, and how the neural circuits in males and females differed. To do this, they genetically engineered specific neurons in the fly to respond to light. This optical trick allowed them to activate the neural circuits that control the behavior pattern directly.
Using a flash of laser light as a "remote control" for the brain cells, the researchers first identified which nerve cells control the courting behavior in males. Next, they showed that the cells were present and functional in both males and females, even though only males do the song and dance.