A new study from the University of Rochester Medical Center suggests that male brains are more focused on having sex instead of eating their meals.
The experiment used C. elegans, a microscopic roundworm that has long been used by researchers to understand fundamental mechanisms in biology, in order to interpret the differences in brain commands that dictate men and women's behaviors.
"While we know that human behavior is influenced by numerous factors, including cultural and social norms, these findings point to basic biological mechanisms that may not only help explain some differences in behavior between males and females, but why different sexes may be more susceptible to certain neurological disorders," said Douglas Portman, Ph.D., an associate professor in the Department of Biomedical Genetics and Center for Neural Development and Disease at the University of Rochester and lead author of the study.
C. elegans live in temperate soil environments, and the team observed the brain activities of the roundworm when exposed to smell. The sense of smell guides the roundworms to a food source, and allows them to avoid danger. The same sense helps them to locate a mate.
Roundworms have two sexes - the males and the hermaphrodites, which can also be females. Both were exposed to food, but the hermaphrodites remained near the food source, while the males wandered and searched for a mate. The only time that the males focused on the food was when they experienced extreme hunger.
The difference in the response from the food source was attributed to the biology of the brains. The team identified the AWA neurons, or the chemoreceptors (ORD-10), which control the strength of sense of smell of the roundworms. The males have lesser ODR-10 than the hermaphrodites, so it is less focused on the food source compared to the females.
To test if the initial analysis was correct, researchers genetically altered both male and hermaphrodite roundworms to switch their sense of smell by modifying their ODR-10. The experiment showed that the males struggled to find their mates, while the hermaphrodites ignored their food source.
"These findings show that by tuning the properties of a single cell, we can change behavior," said Portman. "This adds to a growing body of evidence that sex-specific regulation of gene expression may play an important role in neural plasticity and, consequently, influence differences in behaviors - and in disease susceptibility - between the sexes."
The study was published in the Oct. 17 issue of Current Biology.
