"The brain tissue they analysed came from the left temporal cortex, a region of the brain involved in emotional and social processing, of four women and four men with epilepsy. The tissue itself was healthy, having been removed to allow doctors to access underlying damaged areas.
The men had up to 52% more synapses per brain "layer" in this region than the women. While the effect of high synaptic density in this region is unknown, the team suspects that there may be other regions where women out-synapse men."
-newscientist.com