The Brains of Anxious People May Perceive the World Differently

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iStock

A study showed that people with generalized anxiety disorder unconsciously label harmless things as threats, which may serve to further their anxiety. These findings were published in the journal Current Biology.

Psychologists recognize several forms of clinical anxiety. The most common is generalized anxiety disorder, or GAD, in which people frequently feel very worried or anxious even when it seems like there’s nothing to worry about. Some studies have suggested that anxiety disorders may stem from a process called overgeneralization.

In overgeneralization, the brain lumps both safe and unsafe things together and labels them all unsafe. For this reason, the researchers also call this the “better safe than sorry” approach. Our brains naturally pay more attention to negative or threatening information in our environments. If anxious people perceive more threats in the world around them, it would make a lot of sense for them to be worried.

To find out if overgeneralization was involved, researchers recruited 28 people diagnosed with GAD and 16 people without anxiety and brought them into the lab. The experiment had two parts: training and testing. In the training section, study participants learned to differentiate between three different sounds. Each sound was tied to a different outcome; pressing a key could lead to winning money (the “positive” tone), losing money (the “negative” tone), or nothing (the “neutral” tone).

In the second phase of the experiment, researchers played 15 different sounds for the participants and asked them to press a key when they heard a sound they recognized from the training phase. If they guessed right, they’d win money, but if they guessed wrong, the researchers would take some of their money back.

Because of the risk of losing money, the best strategy for everyone would be a conservative one—not pressing the button much at all based on the assumption that most of the tones were new. But anxious participants were trigger-happy, believing they’d heard many of the unfamiliar tones before. The experience of winning and losing money in training had made a strong emotional impression on them, which led them to overgeneralize new information as relevant.

The researchers also administered brain scans during the testing phase. They found notable differences between anxious and non-anxious brains. While they were focused on parsing new information, anxious people showed more activation in several parts of the brain, including the amygdala, a region associated with fear and worry.

"We show that in patients with anxiety, emotional experience induces plasticity in brain circuits that lasts after the experience is over," senior co-author Rony Paz said in a press release. "Such plastic changes occur in primary circuits that later mediate the response to new stimuli, resulting in an inability to discriminate between the originally experienced stimulus and a new similar stimulus. Therefore, anxiety patients respond emotionally to such new stimuli as well, resulting in anxiety even in apparently irrelevant new situations. Importantly, they cannot control this, as it is a perceptual inability to discriminate."

Paz noted that in dangerous circumstances, the hyper-vigilance associated with anxiety might be a good thing. The problem is that most circumstances aren’t dangerous. "Anxiety traits can be completely normal, and even beneficial evolutionarily," he says. "Yet an emotional event, even minor sometimes, can induce brain changes that might lead to full-blown anxiety."

Shocker: This Electric Eel Delivers More Voltage Than Any Creature on Earth

stacey_newman/iStock via Getty Images
stacey_newman/iStock via Getty Images

Eels are proving to be more slippery than previously believed. A newly identified species of these skinny fish (yes, eels are really fish) delivers more electric voltage than any other creature on the planet.

All species in their taxonomic order (Gymnotiformes) are capable of producing a modest electrical field to help them navigate, a perk that compensates for their poor vision. But electric eels (in the genus Electrophorus) pack a far more potent punch. They bear three organs full of cells that can produce electricity on demand. The cells act as a defense mechanism and can effectively taser prey into submission.

In a study published in Nature Communications, researchers collected more than 100 electric eels in the Amazon region and analyzed their DNA, voltage, and habitat. To their surprise, they found that the single known species of electric eel, Electrophorus electricus, was actually three distinct species. They gave the two new ones the very heavy metal names of E. varii and E. voltai. The latter (named for Alessandro Volta, who invented the electric battery) produced the strongest shock: 860 volts, topping the previous record of 650 volts.

Why the varying strength? The researchers suggested that some eels occupy water with low salt content, and therefore reduced conductivity. A stronger charge may be needed to deliver an effective jolt.

While those numbers sound formidable, their low current means a shock wouldn’t necessarily be harmful to a human. Voltage is the measure of pressure of the flow of electrons; current, or amperage, is the volume of electrons. Eels have high voltage but low current; household power outlets have lower voltage but more current and can be deadly. Eels might startle you with a shock, but it won't be fatal.

If you should find yourself in a school of electric eels bent on subduing you, however, the shocks could result in brief incapacitation that could lead to drowning or an aggravation of an existing heart condition. The study authors hope to eventually film a coordinated eel attack on (non-human) prey.

The discovery of two new species was “quite literally shocking,” lead author Carlos David de Santana told The New York Times.

[h/t Phys.org]

Does the Full Moon Really Make People Act Crazy?

iStock.com/voraorn
iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception: in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

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