Posts Tagged ‘brain’

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Evidence Rebuts Chomsky’s Theory of Language Learning

September 14, 2016

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The idea that we have brains hardwired with a mental template for learning grammar—famously espoused by Noam Chomsky of the Massachusetts Institute of Technology—has dominated linguistics for almost half a century. Recently, though, cognitive scientists and linguists have abandoned Chomsky’s “universal grammar” theory in droves because of new research examining many different languages—and the way young children learn to understand and speak the tongues of their communities. That work fails to support Chomsky’s assertions.

The research suggests a radically different view, in which learning of a child’s first language does not rely on an innate grammar module. Instead the new research shows that young children use various types of thinking that may not be specific to language at all—such as the ability to classify the world into categories (people or objects, for instance) and to understand the relations among things. These capabilities, coupled with a unique hu­­­man ability to grasp what others intend to communicate, allow language to happen. The new findings indicate that if researchers truly want to understand how children, and others, learn languages, they need to look outside of Chomsky’s theory for guidance.

Read HERE

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Nanoparticles may harm the brain

July 14, 2014

A simple change in electric charge may make the difference between someone getting the medicine they need and a trip to the emergency room—at least if a new study bears out. Researchers investigating the toxicity of particles designed to ferry drugs inside the body have found that carriers with a positive charge on their surface appear to cause damage if they reach the brain.

These particles, called micelles, are one type of a class of materials known as nanoparticles. By varying properties such as charge, composition, and attached surface molecules, researchers can design nanoparticles to deliver medicine to specific body regions and cell types—and even to carry medicine into cells. This ability allows drugs to directly target locations they would otherwise be unable to, such as the heart of tumors. Researchers are also looking at nanoparticles as a way to transport drugs across the blood-brain barrier, a wall of tightly connected cells that keeps most medication out of the brain. Just how safe nanoparticles in the brain are, however, remains unclear.

So Kristina Bram Knudsen, a toxicologist at the National Research Centre for the Working Environment in Copenhagen, and colleagues tested two types of micelles, which were made from different polymers that gave the micelles either a positive or negative surface charge. They injected both versions, empty of drugs, into the brains of rats, and 1 week later they checked for damage. Three out of the five rats injected with the positively charged micelles developed brain lesions. The rats injected with the negatively charged micelles or a saline control solution did not suffer any observable harm from the injections, the team will report in an upcoming issue of Nanotoxicology.

Knudsen speculates that one of the attributes that makes positive micelles and similar nanoparticles such powerful drug delivery systems may also be what is causing the brain damage. Because cells have a negative charge on their outside, they attract positively charged micelles and bring them into the cell. The micelles’ presence in the cell or alteration of the cell’s surface charge, she says, may disrupt the cell’s normal functioning.

Negatively charged nanoparticles can also enter cells, according to other research. However, they do so less readily and must be able to overcome the repulsion between themselves and the cell surface. It is possible that the reason the negatively charged micelles were not found to be toxic was that they did not invade cells to the same extent as the positively charged micelles.

The findings are intriguing, says biomedical engineer Jordan Green of Johns Hopkins University in Baltimore, Maryland. But he cautions that there is no evidence that all positively charged nanoparticles behave this way. Other factors can also play a role in the toxicity of nanoparticles, adds pharmaceutical expert Jian-Qing Gao of Zhejiang University in Hangzhou, China. The size and concentration of the particles, as well as the strain of rat used, could all have influenced the results, he says.

Text and Image via ScienceMag

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How the brain creates visions of God

May 13, 2014

For most of recorded history, human beings situated the mind — and by extension the soul — not within the brain but within the heart. When preparing mummies for the afterlife, for instance, ancient Egyptian priests removed the heart in one piece and preserved it in a ceremonial jar; in contrast, they scraped out the brain through the nostrils with iron hooks, tossed it aside for animals, and filled the empty skull with sawdust or resin. (This wasn’t a snarky commentary on their politicians, either—they considered everyone’s brain useless.) Most Greek thinkers also elevated the heart to the body’s summa. Aristotle pointed out that the heart had thick vessels to shunt messages around, whereas the brain had wispy, effete wires. The heart furthermore sat in the body’s center, appropriate for a commander, while the brain sat in exile up top. The heart developed first in embryos, and it responded in sync with our emotions, pounding faster or slower, while the brain just sort of sat there. Ergo, the heart must house our highest faculties.

Meanwhile, though, some physicians had always had a different perspective on where the mind came from. They’d simply seen too many patients get beaned in the head and lose some higher faculty to think it all a coincidence. Doctors therefore began to promote a brain-centric view of human nature. And despite some heated debates over the centuries—especially about whether the brain had specialized regions or not—by the 1600s most learned men had enthroned the mind within the brain. A few brave scientists even began to search for that anatomical El Dorado: the exact seat of the soul within the brain.

Read full article written by Sam Kean at SALON.
Image above: Eugene Thirion’s “Jeanne d’Arc” (1876)

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Seeing In The Pitch-Dark Is All In Your Head

November 8, 2013

A few years ago, cognitive scientist Duje Tadin and his colleague Randolph Blake decided to test blindfolds for an experiment they were cooking up.

They wanted an industrial-strength blindfold to make sure volunteers for their work wouldn’t be able to see a thing. “We basically got the best blindfold you can get.” Tadin tells Shots. “It’s made of black plastic, and it should block all light.”
Tadin and Blake pulled one on just to be sure and waved their hands in front of their eyes. They didn’t expect to be able to see, yet both of them felt as if they could make out the shadowy outlines of their arms moving.
Being scientists, they wondered what was behind the spooky phenomenon. “We knew there wasn’t any visual input there,” Tadin says. They figured their minds were instinctively filling in images where there weren’t any.

After conducting several experiments involving computerized eye trackers, they proved themselves right. Between 50 and 75 percent of the participants in their studies showed an eerie ability to “see” their own bodies moving in total darkness. The research, put together by scientists at the University of Rochester and Vanderbilt University, is published in the journal Psychological Science.

How were they so sure? “The only way you can produce smooth eye movements is if you’re following a target,” Tadin tells Shots. When our eyes aren’t tracking something very specific, they tend to jerk around randomly. “If you just try to make your eyes move smoothly, you can’t do it.” The researchers used this knowledge to test whether people could really distinguish their hand movements in the dark.

Text and Image via Neuromorphogenesis

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Don’t Forget the Brain Is as Complex as All the World’s Digital Data

October 22, 2013

Twenty years ago, sequencing the human genome was one of the most ambitious science projects ever attempted. Today, compared to the collection of genomes of the microorganisms living in our bodies, the ocean, the soil and elsewhere, each human genome, which easily fits on a DVD, is comparatively simple. Its 3 billion DNA base pairs and about 20,000 genes seem paltry next to the roughly 100 billion bases and millions of genes that make up the microbes found in the human body.

And a host of other variables accompanies that microbial DNA, including the age and health status of the microbial host, when and where the sample was collected, and how it was collected and processed. Take the mouth, populated by hundreds of species of microbes, with as many as tens of thousands of organisms living on each tooth. Beyond the challenges of analyzing all of these, scientists need to figure out how to reliably and reproducibly characterize the environment where they collect the data.

“There are the clinical measurements that periodontists use to describe the gum pocket, chemical measurements, the composition of fluid in the pocket, immunological measures,” said David Relman, a physician and microbiologist at Stanford University who studies the human microbiome. “It gets complex really fast.”

Excerpt from an article by Emily Singer at Quanta. Continue THERE

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Einstein’s Brain (…and the neuroscientist who studied it)

October 10, 2013

Marian Diamond began her graduate work in 1948 and was the first female student in the department of anatomy at UC Berkeley. The first thing she was asked to do when she got there was sew a cover for a large magnifying machine (?!?!?!?!).

“They didn’t know what to do with me because they weren’t used to having a woman. They thought I was there to get a husband. I was there to learn.”

Such challenges were not uncommon. Years later she requested tissue samples of Albert Einstein’s brain from a pathologist in Missouri. He didn’t trust her.

“He wasn’t sure that I was a scientist. This is one thing that you have to face being a woman. He didn’t think that I should be the one to be looking at Einstein’s brain.”

Marian persisted for three years, calling him once every six months, and received four blocks of the physicist’s brain tissue (about the size of a sugar cube).

Her research found that Einstein had twice as many glial cells as normal males — the discovery caused an international sensation as well as scientific criticism.

What are glial cells? Previously, scientists believe that neurons were responsible for thinking and glial cells were support cells in the brain. Now Researchers believe the glial cells play a critical role in brain development, learning, memory, aging and disease.

All text and Images via UC Research

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Neurons Could Outlive the Bodies That Contain Them

October 10, 2013

Most of your body is younger than you are. The cells on the topmost layer of your skin are around two weeks old, and soon to die. Your oldest red blood cells are around four months old. Your liver’s cells will live for around 10 to 17 months old before being replaced. All across your organs, cells are being produced and destroyed. They have an expiry date.

In your brain, it’s a different story. New neurons are made in just two parts of the brain—the hippocampus, involved in memory and navigation, and the olfactory bulb, involved in smell (and even then only until 18 months of age). Aside from that, your neurons are as old as you are and will last you for the rest of your life. They don’t divide, and there’s no turnover.

But do neurons have a maximum lifespan, just like skin, blood or liver cells? Yes, obviously, they die when you die, but what if you kept on living? That’s not a far-fetched question at a time when medical and technological advances promise to prolong our lives well past their usual boundaries. Would we reach a point when our neurons give up before our bodies do?

Image above: Stainless steel sculpture “Neuron” by Roxy Paine. Outside the Museum of Contemporary Art, Sydney.
Excerpt from an article written by Ed Yong at NATGEO. Continue THERE