Engaging in sex alters structure of certain regions of the brain that differ in size between males and females, Japanese researchers say. They have pointed out that there are several brain regions linked to sexual behaviour that differ in size between the sexes in humans and other mammals.
Shinji Tsukahara and his colleagues at Saitama University near Tokyo wanted to find out whether a region known to be bigger in males was altered by sex. They compared the brains of male rats who had never had sex before with their more experienced counterparts.
They discovered that the number of spiny structures located at the neuronal synapses was significantly lower in rats that had copulated, New Scientist reported. Tsukahara believes that hormonal changes triggered by the presence of the female, as well as sensory inputs from the penis may be behind the decrease in spines.
These regions may serve as "a one-way road to learn how to mate", he suggested. Once they have been activated for the first time, they may be lost, as they are no longer needed. The spines also play a part in the sexual behaviour of female rats. Tsukahara presented the findings at the recent Society for Neuroscience meeting in Washington DC.