862 posts tagged Science
If we want to understand what’s happening in the brain when people ‘hear voices’, we first need to understand what happens during ordinary inner speech
Most of us will be familiar with the experience of silently talking to ourselves in our head. Perhaps you’re at the supermarket and realise that you’ve forgotten to pick up something you needed. “Milk!” you might say to yourself. Or maybe you’ve got an important meeting with your boss later in the day, and you’re simulating – silently in your head – how you think the conversation might go, possibly hearing both your own voice and your boss’s voice responding. This is the phenomenon that psychologists call “inner speech”, and they’ve been trying to study it pretty much since the dawn of psychology as a scientific discipline. In the 1930s, the Russian psychologist Lev Vygotsky argued that inner speech developed through the internalisation of “external”, out-loud speech. If this is true, does inner speech use the same mechanisms in the brain as when we speak out loud? We have known for about a century that inner speech is accompanied by tiny muscular movements in the larynx, detectable by a technique known as electromyography. In the 1990s, neuroscientists used functional neuroimaging to demonstrate that areas such as the left inferior frontal gyrus (Broca’s area), which are active when we speak out loud, are also active during inner speech. Furthermore, disrupting the activity of this region using brain stimulation techniques can interrupt both “outer” and inner speech. So the evidence that inner speech and speaking out loud share similar brain mechanisms seems pretty convincing. One worry, though, is whether the inner speech we get people to do in experiments is the same as our everyday experience of inner speech. As you might imagine, it’s quite hard to study inner speech in a controlled, scientific manner, because it is an inherently private act.
I Contain Multitudes
Our bodies are a genetic patchwork, possessing variation from cell to cell. Is that a good thing?
Your DNA is supposed to be your blueprint, your unique master code, identical in every one of your tens of trillions of cells. It is why you are you, indivisible and whole, consistent from tip to toe. But that’s really just a biological fairy tale. In reality, you are an assemblage of genetically distinctive cells, some of which have radically different operating instructions. This fact has only become clear in the last decade. Even though each of your cells supposedly contains a replica of the DNA in the fertilized egg that began your life, mutations, copying errors and editing mistakes began modifying that code as soon as your zygote self began to divide. In your adult body, your DNA is peppered by pinpoint mutations, riddled with repeated or rearranged or missing information, even lacking huge chromosome-sized chunks. Your data is hopelessly corrupt. Most genome scientists assume that this DNA diversity, called “somatic mutation” or “structural variation,” is bad. Mutations and other genetic changes can alter the function of the cell, usually for the worse. Disorderly DNA is a hallmark of cancers, and genomic variation can cause a suite of brain disorders and malformations. It makes sense: Cells working off garbled information probably don’t function very well. Most research to date has focused on how aberrant DNA drives disease, but even healthy bodies harbor genetic disorder. In the last few years, some researchers report that anywhere from 10 to 40 percent of brain cells and between 30 and 90 percent of human liver cells are aneuploid, meaning that one entire chromosome is either missing or duplicated. Copy number variations, in which chunks of DNA between 100 and a few million letters in length are multiplied or eliminated, also seem to be widespread in healthy people. (via Our Body as Genetic Patchwork: Helpful or Hurtful? | Simons Foundation)
Simulation studies on emotion have shown that facial actions can initiate and modulate particular emotions. However, the neural mechanisms of these initiating and modulating functions are unclear. In this study, we used resting-state functional magnetic resonance imaging (fMRI) and task-based fMRI to explore these processes by examining spontaneous cerebral activities and brain activations under two conditions: holding a pen using only the teeth (HPT: facilitating the muscles typically associated with smiling) and holding a pen using only the lips (HPL: inhibiting the muscles typically associated with smiling). The resting-state fMRI results showed that compared with the HPL condition, signiﬁcant increases in the amplitudes of low-frequency ﬂuctuations were found in the right posterior cingulate gyrus [PCG; Brodmann area 31 (BA31)] and in the left middle frontal gyrus (MFG; BA9) in the HPT condition. These findings might be related to the initiation of positive emotions (PCG) and to the control and allocation of attention (MFG). The task-based fMRI results showed that the inferior parietal lobule, left supplementary motor area, superior parietal lobule, precuneus, and bilateral middle cingulum were active when facial manipulation influenced the recognition of emotional facial expressions. These results demonstrate that facial actions might not only initiate a particular emotion and draw attention, but also influence face-based emotion recognition.
Locals call it the “Switzerland of Maine” for its breathtaking mountains and picturesque waters, yet Dedham is just one of a cadre of communities in The Pine Tree State where tap water may not be as safe as it appears. Like the majority of the state, many of Dedham’s denizens rely on private wells for the water they drink, bathe in and perhaps use to make infant milk formula. But the water trickling from the tap—unlike water from its public water sources—goes untested and is not subject to any state or federal guidelines. And although homeowners are encouraged to get their water regularly tested to ensure that worrisome levels of bacteria or naturally occurring minerals have not crept in, many residents do not follow that advice. Yet newly available data, released in recent months, indicates that in some 10 communities in the state wells harbor dangerously high levels of fluoride. In some cases, the wells contain more than double the level that the U.S. Environmental Protection Agency has deemed the acceptable maximum exposure level. In small quantities fluoride is known for helping to tamp down the blight of tooth decay; most municipalities in the U.S. add it to their water supplies as a public health measure. The U.S. Centers for Disease Control and Prevention recognizes water fluoridation as one of the top 10 greatest public health achievements of the 20th century. But at higher levels, fluoride can lead to pitted teeth and discoloration. It also makes bones brittle and more prone to fractures. And recent studies have also linked high levels of fluoride exposure with IQ deficits. A 2012 review article examined some two dozen relevant studies performed outside the U.S.—mostly in China but also a couple in Iran—and found that high fluoride exposures reduce children’s IQs by an average of about seven points. (The studies did not all account for exposures to other potentially harmful substances such as lead, but the sheer volume of them does raise concerns about this association.) Mainers may be sipping similar amounts of fluoride. “The sort of levels we’re talking about that are high in China are the sort of levels we see in some private wells,” says Andrew Smith, Maine state toxicologist.
Clear material on windows harvests solar energy
A new type of “transparent” solar concentrator can be used on windows or mobile devices to harvest solar energy without obscuring the view. Past efforts to create similar materials have been disappointing, with inefficient energy production or highly colored materials. “No one wants to sit behind colored glass,” says Richard Lunt, an assistant professor of chemical engineering and materials science at Michigan State University. “It makes for a very colorful environment, like working in a disco. We take an approach where we actually make the luminescent active layer itself transparent.” The solar harvesting system uses small organic molecules developed by Lunt and his team to absorb specific nonvisible wavelengths of sunlight. “We can tune these materials to pick up just the ultraviolet and the near infrared wavelengths that then ‘glow’ at another wavelength in the infrared,” he says. The “glowing” infrared light is guided to the edge of the plastic, where it is converted to electricity by thin strips of photovoltaic solar cells. “Because the materials do not absorb or emit light in the visible spectrum, they look exceptionally transparent to the human eye,” Lunt says. (via Clear material on windows harvests solar energy - Futurity)
An émigré from Nazi Germany, Hans Bethe joined Cornell’s physics department back in 1935. There, he built a remarkable career for himself. A nuclear physicist, Bethe made key contributions to the Manhattan Project during World War II. After the war, he brought stellar young physicists like Richard Feynman from Los Alamos to Ithaca and turned Cornell’s physics department into a top-notch program. In 1967, he won the Nobel Prize for “his groundbreaking work on the theory of energy production in stars.” As a tribute to Bethe, Cornell now hosts a web site called Quantum Physics Made Relatively Simple, where you can watch three lectures presented by Bethe in 1999. They’re a little different from the usual lectures you encounter online. In these videos, Bethe is 93 years old, older than your average prof. And he presents the lectures not in a Cornell classroom, but at the Kendal of Ithaca retirement community, which gives them a certain charm. You can watch them here: Lecture 1: Here Bethe “introduces quantum theory as ‘the most important discovery of the twentieth century’ and shows that quantum theory gave us ‘understanding and technology.’ He cites computers as a dramatic realization of applied quantum physics.” Lecture 2: “By the 1920s, physicists were driving to synthesize early quantum ideas into a consistent theory. In Lecture 2, Professor Bethe relates the exciting theoretical and experimental breakthroughs that led to modern quantum mechanics.”
How Microscopic Ocean Life May Help Make It Rain
SAN FRANCISCO—Clouds can carry millions of pounds of water, but that doesn’t mean rain and snow just happen. Hundreds of thousands of water vapor molecules need to freeze together as ice before they are heavy enough to fall to the ground. But, the water molecules need a bit of dust or other microscopic matter to latch onto in order to get started, and some of the best bits for forming ice are pieces of once-living cells. Scientists now believe a lot of the organic matter in clouds is released into the air by breaking waves in the ocean. In a presentation Aug. 13 here at the American Chemical Society’s annual meeting, atmospheric chemist Kim Prather of UC San Diego said that wave spray might be an important contributor to rain and snow fall. She is the director of the Center for Aerosol Impacts on Climate and the Environment , a research group that is measuring the organic particles released from waves, and matching those to particles they’ve found in rain- and snow-bearing clouds. In the dry west, rain usually forms first as ice. But, ice isn’t a temperature, it’s a structure. It forms when the hydrogen and oxygen atoms in water molecules lock together in a hexagonal pattern that looks like chicken wire. When enough water particles freeze together, they become heavy enough to fall to the ground. If the air below the cloud is warm enough, the ice bits melt into liquid rain. Otherwise, it falls as snow or freezing rain.
Scientists have known for a long time that rain drops form around particles in the clouds, called condensation nuclei. (On their own, water molecules won’t form ice until they reach -36° F.) But, not all condensation nuclei are created equal. Ice can form around pollution particles, but because they are too small and reflective, the ice tends to melt before it gathers enough to fall. On mineral dust, ice won’t form above 5° F. Itty bits of organic matter have a lattice pattern that closely resembles the hexagonal molecular structure of ice. These particles can gather ice at temperatures up 32° F. (via How Microscopic Ocean Life May Help Make It Rain | Science | WIRED)
Your body is home to about 100 trillion bacteria and other microbes, collectively known as your microbiome. Naturalists first became aware of our invisible lodgers in the 1600s, but it wasn’t until the past few years that we’ve become really familiar with them. This recent research has given the microbiome a cuddly kind of fame. We’ve come to appreciate how beneficial our microbes are — breaking down our food, fighting off infections and nurturing our immune system. It’s a lovely, invisible garden we should be tending for our own well-being. But in the journal Bioessays, a team of scientists has raised a creepier possibility. Perhaps our menagerie of germs is also influencing our behavior in order to advance its own evolutionary success — giving us cravings for certain foods, for example. Maybe the microbiome is our puppet master.
Continue reading the main story
Related Coverage More Matter Columns
Thousand-strong robot swarm throws shapes, slowly
Engineers in the US have built a swarm of 1,000 little robots that can shuffle into specific formations on command.
Each of the identical robots is given a picture of the required shape, and then they work together to make it happen. It takes up to 12 hours, but then this is the biggest throng of robots ever built and studied in this way. Inspired by biological examples, like cells forming organs or ants building bridges, the work could help develop self-assembling tools and structures. “Each robot is identical and we give them all the exact same program,” explained Dr Michael Rubenstein, the first author of the study, which is published in Science. “The only thing they have to go on, to make decisions, is what their neighbours are doing.” (via BBC News - Thousand-strong robot swarm throws shapes, slowly)