New York, Sep 19, 2017: Brain structures that control aggressive and sexual behaviour are controlled differently in females, but they tend to overlap in males, a new study has found.
Male circuits for sex and aggression were earlier traced to a distinct part of the hypothalamus, known as the ventromedial hypothalamus, or VMHvl — located on the underside of the hypothalamus in both mice and humans.
The study, conducted on mice, showed that the cells controlling these behaviours are separate in female mice, in both those that have not mated and are new mothers.
While the cells for aggression are close to the centre of the hypothalamus, cells for sexual behaviour are at the edge.
“But in the male, the cells are totally mixed up and overlapped,” said Dayu Lin, Assistant Professor at NYU Langone Health in New York, US.
Having a detailed breakdown of brain functions by gender, is a “fundamental step” toward any future attempt to develop drugs that suppress extreme aggression in humans, Lin added in the paper published in the journal Nature Neuroscience.
Further, the researchers found that turning VMHvl cells on or off did control whether female mice would fight.
Experiments showed that the VMHvl cells that females actively used for transmitting signals, or “firing,” while mating were different from the cells used when they were fighting.
But in male mice, many of the same cells were firing during both activities, the researchers said.
In rural Malawi, families send girls as young as 12 years old for “initiation,” a traditional, cultural practice that marks a child’s entry into adulthood. But child rights campaigners say the ritual entices young girls into early sex, marriage, and teenage pregnancy — forcing many to drop out of school. One local organization is seeking to change this by teaching initiation counselors to give girls age-appropriate information.
Madalitso Makosa was 13 years old when she underwent a traditional, Malawian initiation ritual to become an adult.
She says after the initiation ceremony, the counselors advised her to perform a Kusasa Fumbi or “removing the dust” ritual with a man of my choice. She chose to sleep with her former boyfriend but, unfortunately, became pregnant.
“Removing the dust” refers to a girl losing her virginity, often without protection, to become an adult. Those who become teenage mothers pay the price for this tradition.
Makosa says when she discovered she was pregnant, she was devastated because she had to drop out of school. She is now struggling to get support to take care of her baby. She wished she had continued with her education.”
During the initiation, counselors show how they prepare girls for marriage and for sex.
Agnes Matemba, is an initiation counselor.
She says she gives girls these lessons so that they should keep their man and prevent him from going out to look for another woman. Because, if he goes out and finds excitement in other women, he is likely to dump her.
Child rights campaigners say the initiation ritual fuels Malawi’s high rate of child marriage. Half the girls here marry before age 18.
Malawian group Youthnet and Counselling, YONECO, wants to keep girls in school with a more age-appropriate initiation ritual.
MacBain Mkandawire is YONECO’s executive director.
“This is a traditional cultural thing that people believe in, and it will be very difficult to just say let us end initiation ceremonies,” Mkandawire said. “But what we are saying is that can we package the curriculum in such way the young people are accessing the correct curriculum at the correct time?”
YONECO is working with initiation counselors and traditional leaders to tone down Malawi’s initiations. Already, some areas are banning the practice of encouraging sex after the ceremony.
Aidah Deleza is also known as Senior Chief Chikumbu.
“We say no, no, no,” Chikumbu said. “This is why we have a lot of girls drop out from school, that is why the population has just shot so high just because of that, just because a lot of girls now they have got babies, most of them they are not in marriage.”