PHOTO: Mario D’Amore

An MIT neuroengineer has discovered a way to genetically modify neurons so that their activity can be temporarily silenced using specific colors of light. The technique, which so far has only been tried on mice, takes advantage of a protein (named Arch) which is expressed by the modified neurons when the animals are exposed to rays of yellow-green light. When the proteins are expressed, they pump protons across the cell membrane, alter the neuron’s voltage, and stop it from firing.

In theory, the discovery (which is strangely beautiful, even in the absence of practical applications) could someday be used to treat disorders, such as epilepsy, that are caused by the overactive firing of neurons in certain parts of the brain. It’s also an extraordinarily finely-tuned tool for safely and selectively turning off brain activity, so researchers can learn what different regions of the brain do.

For more, check out the MIT news release or the group’s website.

A new study of older adults and sex, released in the British Medical Journal, finds that men are more likely than women “to be sexually active, report a good quality sex life, and be interested in sex.” In addition, when it comes to being sexually active, women...don’t live as long.

When calculated from age 30, sexual life expectancy for men is nearly 35 years, while sexual life expectancy for women is closer to 31. Those numbers are fairly close, but there’s a key denominator difference - men, on average, die younger than women, leaving women with a greater percentage of their older years in a sexually inactive state.

But, most interestingly, long-term relationships tend to increase women’s sexual life expectancies.

...the gender gap of sexual activity virtually disappeared in those who were married or living with a partner. And in an endorsement of eating right and getting your exercise, health was strongly associated with sexuality in both midlife and later life (whether good health leads to sexuality or vice versa cannot be parsed from the data).

Thanks to the University of Chicago Medical Center’s blog, which I love, for the hat tip.

A new study of 19,567 Chinese subjects found that daily naps increased the risk of developing Type 2 diabetes from 13.5% (without naps) to 15.1% (with naps). In addition, there was some evidence that longer siestas raised the risk more than shorter snoozes.

According to the authors, napping in China is a social norm, which is practiced by all ages primarily as a habit started in childhood. In Western countries, napping is less common and is often unplanned and prompted by sleepiness likely caused by aging, deteriorating health status or nighttime complaints....The authors noted that the association between napping and diabetes was observed despite the fact that nappers had higher levels of physical activity, which has been shown to reduce the risk of diabetes.

Lead author Neil Thomas, PhD, reader in epidemiology at the University of Birmingham, U.K., said that additional research is needed to determine if napping itself plays a causative role in the development of type 2 diabetes, or if other factors are involved.

You can read the study abstract here.

(PHOTO: Addrox Karpenkopf.)

Japanese computer scientists are awesome, aren’t they? I mean, really. They’ve gone and made a program that can tell new parents if their baby is crying because it’s in pain, or just because.

The team has employed sound pattern recognition approach that uses a statistical analysis of the frequency of cries and the power function of the audio spectrum to classify different types of crying. They were then able to correlate the different recorded audio spectra with a baby’s emotional state as confirmed by the child’s parents. In their tests recordings of crying babies with a painful genetic disorder, were used to make differentiating between the babies’ pained cries and other types of crying more obvious. They achieved 100% success rate in a validation to classify pained cries and “normal” cries.

No word on whether the program can translate complex sentences, such as “Stop pinching my cheeks or I’ll bite you, lady!”

Via Eureka News.

From Proto magazine comes a nice round-up of the latest advances in restoring vision, including artificial retinas (like hearing aids for your eyes), gene therapy, and stem-cell treatments that may be able to regrow damaged retina cells.

The piece has a great opening line: “How many electrodes can fit on the back of an eye?” (Answer: In about five years, hopefully 1,000.)

PHOTO: Alice Rosen

Okay, it’s clear that scents contribute to our experience of flavor—that’s the reason strong-smelling food is the only kind you can taste when you’re stuffed up—but can flavor contribute to our experience of smell? How weird would that be?

Weird enough to be true, I guess. Brandeis neuroscientists recently had rats sniff and eat a particular kind of food while their taste cortex was knocked out (I love that researchers can just knock shit out like that. I’d like them to knock out my procrastination cortex). Then they reactivated the taste cortex and gave the rats the same food to sniff--but this time the animals didn’t recognize it, and were less likely to eat it. So the scientists knocked out the taste cortex again, and the rats went for the food. In other words, the taste and olfactory systems each seem to contribute a piece of sensory information that is combined in the brain to produce a unique...um...food stamp.

My favorite part of this study is that it relies heavily on rats wanting to sniff each other’s breath--the mechanism the scientists used to introduce the food odors. Seems rats, unlike people, love the whiffs of old lunch their peers produce.

PHOTO: Dolphin stomach infested with parasites, by Jeremy Sternberg

Delusional parasitosis is a rare and uncomfortable condition in which people come to be convinced—quite falsely—that they have been infested by parasites. There’s no single cause of delusional parasitosis; sometimes it arises as a manifestation of some underlying psychiatric disorder, such as schizophrenia, but in other cases it emerges in otherwise seemingly healthy, rational people.

I’ve just come across a fascinating case study of eight patients with DP in Singapore, notable because it contains detailed descriptions of the beliefs and behaviors inspired by the condition. One 65-year-old housewife complained of “threadlike worms dropping from pigeon droppings, then becoming insects which fly off from her hair.” She said she heard the noises made by the insects as they bit her, a sound like “tuck, tuck, tuck.” She poured kerosene on her head to try to kill them. A 60-year-old fruit seller saw “small, black, thorny parasites with 8 legs crawling in his skin,” which he believed had been caused by black magic directed at him by another seller in the market where he worked. This man was so tormented by his condition that he tried to hang himself three times.

You can read the entire article here.

(One final note: Many doctors contend delusional parasitosis is behind the strange symptoms reported by people who believe they have a controversial disorder known as Morgellons Disease. So far Morgellons has not been widely accepted as a real diagnosis in the medical community, but so many patients have complained about their terrible suffering, which purportedly includes the discovery of bizarre and unidentifiable fibers lodged beneath their skin, that the CDC recently launched an epidemiological study of it.)

PHOTO:Miles Tsang

This tragic, yet somehow life-affirming, story comes to us via the inimitable Improbable Research, creators of the Ig Nobel Prizes. You should all subscribe to their newsletter and site feeds post haste.

This report describes the difficulty in evaluating a patient with multiple traumas because he was covered with paint poured from a truck in a car accident...A 29-year-old male patient was admitted to the emergency department following the collision of his car with a paint-carrying truck. His head, face, neck and hands were covered with a cyan-blue oil paint, and bloody “paint mud” covered all frontal and occipital areas of the scalp.

CONCLUSION: Removal of the paint from the skin and the eyes was a prerequisite for the evaluation of the underlying structures. It is difficult to find a cleansing material that can be used effectively and safely in different parts of the body.

You can read the full paper here.

Photo: Proto Magazine

The marvelously well-researched and always provocative medical news magazine Proto, for which I occasionally write, has an intriguing story in this fall’s issue. Called “Between the Lines,” it’s a piece about how the online patient community Inspire.com is among a few such medically-oriented social networking sites that is beginning to use sophisticated natural language processing techniques borrowed from computer science to mine posts for clinically relevant information linking particular medications with symptoms and side-effects. Here’s a snippet from the article:

A query for mentions of the multiple sclerosis drug Avonex, for example, would parse a post by one user who writes, “i felt worse on avonex than my ms made me feel. while on avonex my psoriasis got VERY VERY bad/worse.” Another post reads, “I have been losing my hair…. I am going to switch from AVONEX to COPAXONE…to see if it is the AVONEX that is causing my hair issues.” After the program sorts through the text, Simetric employees review the results, double-checking the computer’s interpretations and dealing with tricky cases. The software may, for example, have trouble with the apparent contradiction of “wicked good” or pass over phrases it hasn’t been programmed to recognize.

The technique is a terrific mash-up of the emerging powers of the social networking phenomenon with the emerging powers of natural language processing, and it’s a really beautiful illustration of what’s possible when you find ways to analyze and quantify information that people naturally want to share with each other. I love it.

Heard on one of the questions in this week’s Not My Job segment of Wait, Wait! Don’t Tell Me!:” a reference to an animated film made by Walt Disney in the 1940s to educate young girls about the salient phenomenon of female puberty, and sponsored by (who else?) Kotex. Peter Sagal: “What’s interesting is the title. The Story of Menstruation—it’s like How it Was Invented!”

Found tonight, and shared with you: the very film in question, all oddly moody blue backdrops, calm female voice-over, and cutesy animations. It’s the least I can do. I really wouldn’t want to be alone in having the bizarre pleasure of hearing and seeing illustrated such words of wisdom as:

“Try not to throw yourself off schedule by getting overtired, emotionally upset, or catching cold.”

“But don’t let it get you down. After all, no matter how you feel, you have to live with people. You have to live with yourself, too. And once you stop feeling sorry for yourself and take those days in your stride, you’ll find it easier to keep smiling and even tempered.”

If you stick around long enough, you’ll get to the counsel in this post’s title, somewhat more gently put.

Just one question, Disney. If you were brave enough to take on what, nearly seventy years ago, was even more sensitive a subject than it is today, sensible enough to actually illustrate it with images of the uterus and fallopian tubes, and scientific enough to take viewers through the hormonal pathway first triggered by the pituitary gland, why then did you totally wuss out and transform menstrual blood into the color of milk? Honestly. There’s a scene where it looks like a alien-head shaped cow is being milked.

P.S. The scene in the screen grab you see above goes along with a bit about how all women, being different, have different menstrual schedules and periods that last for differing amounts of time. Why this message is accompanied by a group of chicks standing around staring at a Scottish Terrier, one of whom appears to be wearing a crown, I can only imagine. Hypotheses are welcome.