The hormone oxytocin might play a special but intense role in regulating female sexual behavior that a new mouse study has revealed.

The study, conducted by the Rockefeller University. The hormone is normally secreted during moments of breastfeeding, childbirth, relationship bonding, and of course sex. The researchers published their data in the journal Cell. The research looked at the genetic makeup of female mice and manipulating them so that they would eliminate any oxytocin responses in their prefrontal cortex. The result was female mice exhibiting no sexual interest in male mice even during their mating cycle peak. Not to embarrass the male mice, but the female mice, according to the study, had as much attention in the males as they did a Lego toy block.

Researchers state that the reason behind this response is due to a newly discovered class of brain cells. The researchers achieved this by identifying new populations of neurons that were activated by the hormone oxytocin. Doing this they uncovered a way the hormone signal impinges on the cells and neurons and their interactions between the mice. It was a search for a new kind of interneuron that delivers messages to the other neurons across short distances.

Researcher Miho Nakajima started creating profiles of the genes that were expressed in the interneurons. She found out that there was a protein in the cortex, a receptor that responded to oxytocin. The discovery piqued her interest in what was the small and scattered population of interneurons behaving in response to the signal and the question was, was oxytocin the trigger? Since oxytocin is signature to females and their social behaviors the researchers decided to target the females for examination and experimentation. Next was to figure out how the oxytocin receptor interneurons (OxtrINs) affected the mice’s behavior. The researcher then targeted only this class of interneurons and silenced them as well as blocked the receptor’s ability to detect the hormone in a separate experiment.

Next came experimentation to see how the females behaved in normal situations. Differences in their behavior were easily detected and their relationships to the male mice significantly changed. One surprise is that some of the females with the silenced OxtrINs showed unexpected interest in the toy Lego block and some just responded in a normal fashion. Further experimentation involved watching the females when they were and weren’t in estrus. The findings panned out and the researchers believe they’re on to something regarding oxytocin and regulating female sexual behavior that might expand to humans as well.