|Alpha Male Mating Habits
The Sex eZine - Sexy Science
Females who select alpha males generate new brain cells, researchers find
July 2nd 2007.
CALGARY - It's not just the muscles, or the confidence, or the chiselled cheekbones. Nor is it the flashy sportscar or the charming arrogance.
No, the charms of the alpha male -- the guy who stands out above lesser mortals -- may actually help women become smarter.
Researchers at the University of Calgary's Hotchkiss Brain Institute have discovered that female mice exposed to the pheromones of dominant males generate new brain cells. And those brain cells help them find other dominant males, a process that boosts the survival of any offspring.
The findings, published this week in the prestigious journal Nature Neuroscience, could have far-reaching benefits that are much more than just providing a boost to the biggest guy at the bar. The work could help treat people with brain injuries.
"A big part of what we try to do is take the knowledge of natural processes and see if it can be applied to medicine," said Dr. Samuel Weiss, a neuroscientist and professor of cell biology and anatomy, and pharmacology and therapeutics at the U of C.
"This is turning brain cells on. These hormones may be natural boosters in brain cell production, they may be used to boost cell production."
Studies show in the animal kingdom, females instinctively select mates who are dominant in order to ensure that those dominant genes are passed to their offspring, increasing their chances of survival.
The U of C study found that female mice, when exposed to pheromones of dominant males, generated new brain cells within two weeks. On the flipside, female mice exposed to the pheromones of subordinate males did not generate new cells.
With the development of the new brain cells, the female mice exposed to the pheromones of the alpha males were then able to successfully select dominant mates.
Pheromones are chemical signals that mammals use to select and remember their mates. Pheromone receptors in mice are virtually identical to those in people.
"We found that pheromones, and particularly dominant male pheromones, can stimulate the production of new brain cells, and these new brain cells are substantially important to allow the females to choose a dominant male," said Weiss.
"They did make a choice, and they chose the dominant male. The link between making the neurons and making the choice is clear."
Weiss' study finds that two areas of the brain - memory and smell -- must work together to form memories of a female's preferred partner. It is the first time the two have been linked in such a way.
"We are able to prove for the first time that new neurons in the seat of memory in the brain, the hippocampus, work hand-in-hand with new neurons in the olfactory bulb," said Weiss.
"Previously, no one understood how the new neurons in these regions of the brain were communicating."
The study, which is ongoing, may eventually result in the stimulation of brain regeneration, something that could be crucial in the recovery of the brain injured.
About 7,500 people in southern Alberta suffer a brain injury every year, almost half from a stroke, aneurysm or heart attacks. The others are the result of trauma related to car crashes, falls, sports incidents and workplace events.
"We anticipate these hormones could be important tools in stimulating brain regeneration, something we are now investigating in the lab," said Weiss, whose research is supported by the Alberta Heritage Foundation for Medical Research, the Canadian Institutes of Health Research and the Canadian Stem Cell Network.
"I think this is the beginning . . . if you can harness a natural process, you may be able to repair the brain. It's really important to understand the natural processes and then take that information and apply it."
The study also suggests a link between brain cell production, pheromones, and the bonding of parents and babies.
First baby born from egg matured in lab and frozen
July 2nd 2007.
LONDON (Reuters) - The first test-tube baby created from an egg matured in the laboratory and then frozen has been born in Canada, in a breakthrough offering hope to women with cancer and others unsuited to normal IVF treatment.
The baby is doing well and another three women are pregnant by the same method, researchers told a medical meeting in Lyon, France, on Monday.
Conventional in vitro fertilization (IVF) involves using high doses of expensive hormone drugs to stimulate the ovaries to produce multiple mature eggs.
But some women seeking to preserve their child-bearing capacity may not have enough time to undergo ovarian stimulation or may have a condition that makes it dangerous, such as hormone-sensitive breast cancer.
For these patients, ripening eggs in the lab -- so-called in vitro maturation (IVM) -- makes sense. Until now, however, scientists have never frozen, thawed and then fertilized a lab-matured egg. This multi-step process increases significantly the flexibility of fertility treatment.
"We have demonstrated for the first time that it is possible to do this and, so far, we have achieved four successful pregnancies, one of which has resulted in a live birth," Hananel Holzer of the McGill Reproductive Center in Montreal said in a statement.
The research is still at an early stage and has not yet been proven in cancer patients, he told the annual meeting of the European Society of Human Reproduction and Embryology (ESHRE).
But Holzer and other experts believe it has the potential to become one of the main options for fertility preservation.
Women diagnosed with cancer are likely to be the main beneficiaries, since cancer treatment can make them sterile and they often have no time to take fertility drugs.
At present, there is the experimental option of having ovarian tissue removed, frozen and transplanted back later. But this brings with it a theoretical risk of re-introducing cancer.
Holzer tried his new technique on 20 infertile women with polycystic ovary syndrome, a leading cause of infertility.
Joep Geraedts, ESHRE's chairman elect, said the resulting four pregnancies, or 20 percent success rate, was "quite good."
"If this works in cancer patients, it might ultimately be possible to do this in all women that undergo IVF or assisted reproduction because then you don't need to bother them with hormones," he told Reuters in a telephone interview.
It could also save money, since treatment with hormone drugs can cost thousands of dollars. Leading makers of fertility drugs include Merck Serono and Akzo Nobel's Organon unit, which is being acquired by Schering-Plough.
Geraedts said there should now be large-scale clinical trials to assess the new procedure definitively.
"Maturing eggs using science could eventually spell the end of sex for procreation. If we can eliminate diseases using genetics the only reason to have sex would be for pleasure."
Sexsomnia: Lust never sleeps
Joseph Hall - June 1st 2007.
Researchers are seeking to formally classify a new family of abnormal sexual behaviours or "sexsomnias" that occur while people are asleep.
Ranging from masturbation to fondling to unconscious rape, sleep-related sexual abnormalities need to be properly categorized and labelled so physicians will recognize them when they crop up, according to a paper published today in the journal SLEEP.
"We wanted to call attention to how sexuality looms throughout all the known disorders of sleep," says Dr. Carlos Schenck, a University of Minnesota psychiatrist and the paper's lead author.
Schenck says a computer search of peer-reviewed journals and other sources uncovered more than 125 cases dating to 1986 that provide the basis for the new classification system. They include:
31 cases resulting from parasomnias, which is especially unstable delta sleep, a period of the slowest brain wave activity. Usually associated with sleepwalking, it has resulted in sexual talking, masturbation, fondling, sexual intercourse and aggressive sexual behaviour. Several rapes have been associated with this sleep state.
Seven incidents of epileptic seizures during sleep that have brought on intense orgasms, grabbing of partners and violent masturbation.
78 cases of Kleine-Levin syndrome, which causes intense and lengthy bouts of sleep.
Dr. Chanth Seyone, a sleep expert and director of the Acquired Brain Injury Clinic at Toronto's University Health Network, says the sexsomnia field is still very contentious among researchers.
In your dreams
Some disorders that can bring on abnormal sexual behaviours: