Why Is Your First Instinct After Hurting Your Finger to Put It in Your Mouth?

iStock
iStock

If you close your fingers in a car door or slam your funny bone into a wall, you might find your first reaction is to suck on your fingers or rub your elbow. Not only is this an instinctive self-soothing behavior, it's a pretty effective technique for temporarily calming pain signals to the brain.

But how and why does it work? To understand, you need to know about the dominant theory of how pain is communicated in the body.

In the 17th century, French scientist and philosopher René Descartes proposed that there were specific pain receptors in the body that "rang a bell in the brain" when a stimulus interacted with the body, Lorne Mendell, a professor of neurobiology and behavior at Stony Brook University in New York, tells Mental Floss. However, no study has effectively been able to identify receptors anywhere in the body that only respond to painful stimuli.

"You can activate certain nerve fibers that can lead to pain, but under other circumstances, they don't," Mendell says. In other words, the same nerve fibers that carry pain signals also carry other sensations.

In 1965, two researchers at MIT, Patrick Wall and Ronald Melzack, proposed what they called the gate control theory of pain, which, for the most part, holds up to this day. Mendell, whose research focuses on the neurobiology of pain and who worked with both men on their pain studies, explains that their research showed that feeling pain is more about a balance of stimuli on the different types of nerve fibers.

"The idea was that certain fibers that increased the input were ones that opened the gate, and the ones that reduced the input closed the gate," Mendell says. "So you have this idea of a gate control sitting across the entrance of the spinal cord, and that could either be open and produce pain, or the gate could be shut and reduce pain."

The gate control theory was fleshed out in 1996 when neurophysiologist Edward Perl discovered that cells contain nociceptors, which are neurons that signal the presence of tissue-damaging stimuli or the existence of tissue damage.

Of the two main types of nerve fibers—large and small—the large fibers carry non-nociceptive information (no pain), while small fibers transmit nociceptive information (pain).

Mendell explains that in studies where electric stimulation is applied to nerves, as the current is raised, the first fibers to be stimulated are the largest ones. As the intensity of the stimulus increases, smaller and smaller fibers get recruited in. "When you do this in a patient at low intensity, the patient will recognize the stimulus, but it will not be painful," he says. "But when you increase the intensity of the stimulus, eventually you reach threshold where suddenly the patient will say, 'This is painful.'"

Thus, "the idea was that shutting the gate was something that the large fibers produced, and opening the gate was something that the small fibers produced."

Now back to your pain. When you suck on a jammed finger or rub a banged shin, you're stimulating the large fibers with "counter irritation," Mendell says. The effect is "a decrease in the message, or the magnitude of the barrage of signals being driven across the incoming fiber activation. You basically shut the gate. That is what reduces pain."

This concept has created "a big industry" around treating pain with mild electrical stimulation, Mendell says, with the goal of stimulating those large fibers in the hopes they will shut the gate on the pain signals from the small fibers.

While counter irritation may not help dull the pain of serious injury, it may come in handy the next time you experience a bad bruise or a stubbed toe.

Mount Vesuvius's Volcanic Eruption Turned One Victim's Brain into Glass

iSoldierr/iStock via Getty Images
iSoldierr/iStock via Getty Images

The heat of Mount Vesuvius’s volcanic eruption turned at least one victim’s brain into glass, new evidence suggests.

This discovery may be unique, researcher Pier Paolo Petrone told National Geographic. It’s rare for archaeologists to uncover brain tissue at all, he said. Due to its lack of much fibrous content, the brain is usually one of the first organs to deteriorate after death. In the rare cases when archaeologists do find preserved brain tissue, it’s usually saponified—or converted into a soapy mixture of glycerol and fatty acids. In this case, the brain matter appears to have been vitrified—liquefied at a high heat and then rapidly cooled to create a glasslike substance.

Petrone and his team aren’t sure what could have enabled the victim’s brain to be vitrified. Charred wood found near the victim’s remains, uncovered at the former site of the town of Herculaneum, indicates potential temperatures of up to 968°F (520°C). It’s unclear what may have caused the rapid cooling that turned the brain into glass, and it’s even more puzzling that brain vitrification has only been discovered in one body—so far.

“This is the first ever discovery of ancient human brain remains, vitrified by heat,” Petrone told NBC News.

[h/t Science Alert]

Here’s What You Need to Know About the New Coronavirus

jarun011/iStock via Getty Images
jarun011/iStock via Getty Images

This article has been updated.

This morning, the Centers for Disease Control and Prevention (CDC) confirmed the fifth case of the recently discovered coronavirus in the U.S. Find out what it is, where it is, how to avoid it, and all the other need-to-know information about the illness below.

What is the new coronavirus?

Coronaviruses are a group of viruses named for the crown-shaped spikes that cover their surfaces (corona is the Latin word for crown). According to the CDC, human coronaviruses can cause upper-respiratory tract illnesses, including the common cold, and can sometimes lead to more severe lower-respiratory tract issues like pneumonia or bronchitis.

Because this latest coronavirus, 2019-nCoV, is so new, health officials are currently trying to figure out how it works and how to treat it. It’s not the first time a potent new coronavirus has caused an international outbreak: SARS-CoV originated in Asia and spread to more than two dozen countries in 2003, and MERS-CoV first infected people in Saudi Arabia before spreading across the globe in 2012.

Where is the coronavirus outbreak happening?

Overall, China has more than 2700 confirmed cases, many of which are in Wuhan, a city in China’s Hubei province where 2019-nCoV was first detected last month. Around 50 additional cases have been reported in South Korea, Japan, Singapore, Hong Kong, Macao, Taiwan, Thailand, and Vietnam.

The CDC has confirmed five U.S. cases—in California, Arizona, Illinois, and Washington—all of whom had recently returned from trips to Wuhan. Right now, the CDC is screening all passengers from Wuhan, and their flights are only allowed to land at one of five U.S. airports: John F. Kennedy International Airport in New York, Los Angeles International Airport, San Francisco International Airport, Hartsfield-Jackson Atlanta International Airport, or Chicago O’Hare International Airport.

Chinese officials have shut down transportation to and from Wuhan, and they’re also temporarily closing tourist spots like Beijing’s Forbidden City, Shanghai Disneyland, and a portion of the Great Wall.

What are the symptoms of the new coronavirus?

Symptoms are similar to those caused by a cold or the flu, including fever, dry cough, and breathing difficulty. As of Monday morning, 81 people in China had died from the virus, and The New York Times reported that older people with preexisting conditions like cirrhosis, diabetes, and Parkinson’s disease are most likely to be affected.

How does the new coronavirus spread?

Because most of the early cases of 2019-nCoV were traced back to a seafood and meat market in Wuhan, health officials think the virus originally spread from infected animals to humans, but it’s now being transmitted from person to person.

Though scientists are still studying exactly how that happens, the leading theory is that it travels in tiny droplets of fluid from the respiratory tract when a person coughs or sneezes.

How do you avoid the new coronavirus?

The CDC is warning everyone to avoid any nonessential trips to Wuhan, and to avoid animals or sick people if you’re traveling elsewhere in China. If you’ve been to China in the last two weeks and experience any of the symptoms listed above, you should seek medical attention immediately—and you should call the doctor’s office or emergency room beforehand to let them know you’re coming.

Otherwise, simply stick to the precautions you’d normally take when trying to stay healthy: Wash your hands often with soap and water, cover your nose and mouth when coughing or sneezing, stay away from sick people, and thoroughly cook any meat or eggs before eating them.

Should you be worried about the new coronavirus?

The global health community is taking 2019-nCoV seriously in order to curb the outbreak as quickly as possible, but you definitely shouldn’t panic. The CDC maintains that it’s a low-risk situation in the U.S., and public health officials are echoing that message.

Caitlin Wolfe, a former consultant epidemiologist for the World Health Organization (WHO) and current doctoral student at the University of South Florida’s College of Public Health, tells Mental Floss that it’s too early to tell if the virus will become a nationwide outbreak, but the fact that cases have been detected in the U.S. “means patients and physicians are paying attention to the relevant symptoms and travel history,” and “the public health systems we have here are working.”

“The most important messages to get out to the American public are ones that share the information we know and avoid the alarmist/sensationalist narrative,” Wolfe says. “Early estimates from the Chinese authorities suggest that the R0, or the average number of people each person with the virus infects, is between 1.4 and 2.5. To put this in perspective, the average number of susceptible people infected by someone with the measles virus is between 12 and 18.”

While experts work to understand and fight the virus, keep an eye out for updates from the CDC and WHO and be extra committed to practicing good hygiene habits—which, as Wolfe points out, will also help protect you from the flu or even just a regular cold.

[h/t USA Today]

SECTIONS

arrow
LIVE SMARTER