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As a woman gets older, physical problems are less likely to influence whether she is sexually active than her partner’s health or interest in sex, according to a new study by researchers at the University of California, San Francisco and Kaiser Permanente.

The study also showed significant differences in the frequency of sexual activity, as well as sexual desire and satisfaction, among racial groups of middle-aged and elderly women. Study results appear in the June 24, 2009 online version of the “Journal of the American Geriatrics Society.”

In the study of nearly 2,000 women, aged 45 to 80 years old, 43 percent reported at least moderate sexual desire, and 60 percent had been sexually active in the previous three months. Half of all sexually active participants described their overall sexual satisfaction as moderate to high. More than one quarter of women aged 65 years or older remained moderately or highly interested in sex, and more than one third of women in this age group had been sexually active in the past three months.

Among sexually inactive women in the entire group, the most common reason was lack of interest in sex (39 percent), followed by lack of a partner (36 percent), physical problem of partner (23 percent) and lack of interest by partner (11 percent). Only nine percent were inactive from personal physical problems.

Sexual activity was defined as any activity that was arousing, including masturbation.

“Our findings indicate that a substantial portion of women are interested and engaged in sexual activity as they age,” said lead author Alison Huang, MD, assistant professor in internal medicine at the University of California, San Francisco. “Clinicians should consider a woman’s overall health when addressing concerns about sexual inactivity. However, treatment directed solely at improving women’s sexual functioning, such as medications, may not substantially affect their activity if partner issues also are not addressed.”

The U.S. population is becoming increasingly diverse and older, as the first wave of baby boomers is turning 65 years old. Researchers evaluated multiple dimensions of sexual functioning among a racially and ethnically diverse group of middle-aged and older women who self–identified demographic characteristics, medical history, medication use and health habits. More than half the women in the overall study were of non-white ethnicity — 20 percent were African American, 18 percent were Latina, and 19 percent were Asian – and over two-thirds of participants were married or living as married.

African American women were more likely than white women to report at least moderate desire but less likely to report weekly sexual activity, and sexually active Latinas were more likely than white women to report at least moderate sexual satisfaction.

“To date, research has focused rather narrowly on the physical factors that contribute to women’s sexual response, and very little analysis has explored sexual function among racially and ethnically diverse women. Further work is needed to understand the differences in self-reported sexual functioning by race, and how they change as women age. Ultimately, this information should help guide clinicians in discussing sexual problems with women of diverse backgrounds,” said Huang.

With thanks to Eurekalert

Humans’ ability to easily distinguish among many faces and recognize people they know goes way, way back, say researchers reporting online on June 25th in Current Biology, a Cell Press publication. That assertion stems from new evidence that, like us, rhesus monkeys tell their friends from foes by picking up on the precise layout of facial features.

“We found that monkeys looking at faces perceive an illusion, the Thatcher effect, that humans experience,” said Robert Hampton of Emory University’s Department of Psychology and Yerkes National Primate Research Center. “This powerful perceptual effect shows that face perception depends on detection of the relations among features in a face, not just on detection of the collection of individual features.”

The discovery means that primates have probably perceived faces in essentially the same way for 30 million years or more, he said.

The Thatcher effect refers to the impaired ability to recognize changes in the relations among features in upside-down versus right-side-up faces. (The phenomenon is so named because it was first shown with the image of Margaret Thatcher.) In demonstrating the effect, scientists manipulate the image of a face so that the eyes and mouth are upside down relative to the rest of the face.

“Surprisingly,” Hampton said, “when the image of a face so modified is presented upside down, most people do not think it looks particularly odd. But when viewed right-side up, it looks awful.” It shows that when we look at faces normally, we are especially sensitive to the relations among features. When faces are upside down, however, we process the image more as a collection of features, with less emphasis on their relations to one another.

In the current study, Hampton and his colleagues showed monkeys pictures of monkey faces until they became “bored,” as indicated by a loss of interest in the images. They then showed them digitally manipulated faces, with the eyes and mouth upside down relative to the rest of the face. When the manipulated faces were shown upright, the monkeys took notice and began studying the pictures again. In contrast, upside-down faces held no new interest and the monkeys continued to ignore them as if nothing were amiss.

The findings offer the first demonstration that a non-human primate species shows the Thatcher effect. “This direct evidence of configural face perception in monkeys, collected under testing conditions that closely parallel those used with humans, indicates that perceptual mechanisms for individual recognition have been conserved through primate cognitive evolution,” the researchers said.

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Mice carrying a “humanized version” of a gene believed to influence speech and language may not actually talk, but they nonetheless do have a lot to say about our evolutionary past, according to a report in the May 29th issue of the journal Cell, a Cell Press publication.

“In the last decade or so, we’ve come to realize that the mouse is really similar to humans,” said Wolfgang Enard of the Max-Planck Institute for Evolutionary Anthropology. “The genes are essentially the same and they also work similarly.” Because of that, scientists have learned a tremendous amount about the biology of human diseases by studying mice.

“With this study, we get the first glimpse that mice can be used to study not only disease, but also our own history.”

Enard said his team is generally interested in the genomic differences that set humans apart from their primate relatives. One important difference between humans and chimpanzees they have studied are two amino acid substitutions in FOXP2. Those changes became fixed after the human lineage split from chimpanzees and earlier studies have yielded evidence that the gene underwent positive selection. That evolutionary change is thought to reflect selection for some important aspects of speech and language.

“Changes in FOXP2 occurred over the course of human evolution and are the best candidates for genetic changes that might explain why we can speak,” Enard said. “The challenge is to study it functionally.”

For obvious reasons, the genetic studies needed to sort that out can’t be completed in humans or chimpanzees, he said. In the new study, the researchers introduced those substitutions into the FOXP2 gene of mice. They note that the mouse version of the gene is essentially identical to that of chimps, making it a reasonable model for the ancestral human version.

Mice with the human FOXP2 show changes in brain circuits that have previously been linked to human speech, the new research shows. Intriguingly enough, the genetically altered mouse pups also have qualitative differences in ultrasonic vocalizations they use when placed outside the comfort of their mothers’ nests. But, Enard says, not enough is known about mouse communication to read too much yet into what exactly those changes might mean.

Although FoxP2 is active in many other tissues of the body, the altered version did not appear to have other effects on the mice, which appeared to be generally healthy.

Those differences offer a window into the evolution of speech and language capacity in the human brain. They said it will now be important to further explore the mechanistic basis of the gene’s effects and their possible relationship to characteristics that differ between humans and apes.

“Currently, one can only speculate about the role these effects may have played during human evolution,” they wrote. “However, since patients that carry one nonfunctional FOXP2 allele show impairments in the timing and sequencing of orofacial movements, one possibility is that the amino acid substitutions in FOXP2 contributed to an increased fine-tuning of motor control necessary for articulation, i.e., the unique human capacity to learn and coordinate the muscle movements in lungs, larynx, tongue and lips that are necessary for speech. We are confident that concerted studies of mice, humans and other primates will eventually clarify if this is the case.”