Learning to Read as an Adult Changes Deep Regions of the Brain

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In the evolutionary history of humans, reading and writing are relatively new functions. As a result, in order to read written language, human brains have had to recruit and adapt parts of the visual system to interface with language centers. This is a process researchers have long believed occurred primarily in the cerebral cortex, the outer layer of the brain. But in a new study where illiterate people in their thirties were trained to read over six months, researchers have discovered that reading actually activates much deeper brain structures as well, opening doors to a better understanding of how we learn, and possible new interventions for dyslexia. Their results were recently published in the journal Science Advances.

In order to learn to read, "a kind of recycling process has to take place in the brain," Falk Huettig, one of the collaborating researchers at Max Planck Institute for Human Cognitive and Brain Sciences, tells Mental Floss by email. "Areas evolved for the recognition of complex objects, such as faces, become engaged in translating letters into language.”

To study this process in the brain, researchers selected participants from India, where the literacy rate is about 63 percent, a rate influenced by poverty, which limits educational access, especially for girls and women. Most of the participants in this study were women in their thirties who came into the study unable to read a single word.

They divided the participants into a group that received reading training intervention and a control group that was not trained. Both groups underwent functional magnetic resonance imaging (fMRI) brain scans before and after the six-month study. Some participants were excluded due to incomplete scanning sessions, leaving a total of 30 participants in the final analysis.

They were taught to read Devanagari, the script upon which Hindi and some other languages of South Asia are based. It's an alpha-syllabic script composed of complex characters that describe whole syllables or words.

The instructor was a professional teacher who followed the locally established method of reading instruction. During the first month of instruction, the participants first were taught to read and write 46 primary Devanagari characters simultaneously. After learning the letters and reading single words, they were taught two-syllable words. In all, they studied approximately 200 words in the first month.

In the second month, the participants were then taught to read and write simple sentences, and in the third month, they learned more complex, three-syllable words. Finally, in the second half of the program, participants learned some basic grammar rules. "For example, the participants learned about the differences between nouns, pronouns, verbs, proverbs, and adjectives, and also about basic rules of tense and gender," Huettig says.

Within six months, participants who could read between zero and eight words even before the training had reached a first-grade level of reading, according to Huettig. "This process was quite remarkable," Huettig says. "Learning to read is quite a complex skill, as arbitrary script characters must be mapped onto the corresponding units of spoken language."

When the researchers looked at the brain scans taken before and after the six-month training, Huettig says they expected to simply replicate previous findings: that changes are limited to the cortex, which is known to adapt quickly to new challenges.

What they didn't expect was to see changes in deeper parts of the brain. "We observed that the learning process leads to a reorganization that extends to deep brain structures in the thalamus and the brainstem." More specifically, learning to read had an impact on a part of the brainstem called the superior colliculus as well as the pulivinar, located in the thalamus, which "adapt the timing of their activity patterns to those of the visual cortex," Heuttig explains.

These deep brain structures help the visual cortex filter important information from the flood of visual input—even before we consciously perceive it. "It seems that these brain systems increasingly fine-tune their communication as learners become more and more proficient in reading," he says.

In essence, the more these participants read, the better they became at it. The research also revealed that the adult brain is more adaptable than previously understood. "Even learning to read in your thirties profoundly transforms brain networks," Huettig says. "The adult brain is remarkably flexible to adapt to new challenges."

Even more promising, these results shed new light on a possible cause of dyslexia, a language-processing disorder, which researchers have long attributed to dysfunctions of the thalamus. Since just a few months of reading training can modify the thalamus, Huettig says, "it could also be that affected people show different brain activity in the thalamus, just because their visual system is less well-trained than that of experienced readers."

Huettig feels that the social implications of this kind of research are huge, both for people effected by dyslexia as well as the hundreds of millions of adults who are completely or functionally illiterate around the world. Huettig says the new findings could help "put together literacy programs that have the best chance of succeeding to help these people."

5 Signs Humans Are Still Evolving

Lealisa Westerhoff, AFP/Getty Images
Lealisa Westerhoff, AFP/Getty Images

When we think of human evolution, our minds wander back to the millions of years it took natural selection to produce modern-day man. Recent research suggests that, despite modern technology and industrialization, humans continue to evolve. "It is a common misunderstanding that evolution took place a long time ago, and that to understand ourselves we must look back to the hunter-gatherer days of humans," Dr. Virpi Lummaa, a professor at the University of Turku, told Gizmodo.

But not only are we still evolving, we're doing so even faster than before. In the last 10,000 years, the pace of our evolution has sped up, creating more mutations in our genes, and more natural selections from those mutations. Here are some clues that show humans are continuing to evolve.

1. Humans drink milk.

Historically, the gene that regulated humans' ability to digest lactose shut down as we were weaned off our mothers' breast milk. But when we began domesticating cows, sheep, and goats, being able to drink milk became a nutritionally advantageous quality, and people with the genetic mutation that allowed them to digest lactose were better able to propagate their genes.

The gene was first identified in 2002 in a population of northern Europeans that lived between 6000 and 5000 years ago. The genetic mutation for digesting milk is now carried by more than 95 percent of northern European descendants. In addition, a 2006 study suggests this tolerance for lactose developed again, independently of the European population, 3000 years ago in East Africa.

2. We're losing our wisdom teeth.

Our ancestors had much bigger jaws than we do, which helped them chew a tough diet of roots, nuts, and leaves. And what meat they ate they tore apart with their teeth, all of which led to worn-down chompers that needed replacing. Enter the wisdom teeth: A third set of molars is believed to be the evolutionary answer to accommodate our ancestors' eating habits.

Today, we have utensils to cut our food. Our meals are softer and easier to chew, and our jaws are much smaller, which is why wisdom teeth are often impacted when they come in — there just isn't room for them. Unlike the appendix, wisdom teeth have become vestigial organs. One estimate says 35 percent of the population is born without wisdom teeth, and some say they may disappear altogether.

3. We're resisting infectious diseases.

In 2007, a group of researchers looking for signs of recent evolution identified 1800 genes that have only become prevalent in humans in the last 40,000 years, many of which are devoted to fighting infectious diseases like malaria. More than a dozen new genetic variants for fighting malaria are spreading rapidly among Africans. Another study found that natural selection has favored city-dwellers. Living in cities has produced a genetic variant that allows us to be more resistant to diseases like tuberculosis and leprosy. "This seems to be an elegant example of evolution in action," says Dr. Ian Barnes, an evolutionary biologist at London's Natural History Museum, said in 2010 statement. "It flags up the importance of a very recent aspect of our evolution as a species, the development of cities as a selective force."

4. Our brains are shrinking.

While we may like to believe our big brains make us smarter than the rest of the animal world, our brains have actually been shrinking over the last 30,000 years. The average volume of the human brain has decreased from 1500 cubic centimeters to 1350 cubic centimeters, which is an amount equivalent to the size of a tennis ball.

There are several different conclusions as to why this is: One group of researchers suspects our shrinking brains mean we are in fact getting dumber. Historically, brain size decreased as societies became larger and more complex, suggesting that the safety net of modern society negated the correlation between intelligence and survival. But another, more encouraging theory says our brains are shrinking not because we're getting dumber, but because smaller brains are more efficient. This theory suggests that, as they shrink, our brains are being rewired to work faster but take up less room. There's also a theory that smaller brains are an evolutionary advantage because they make us less aggressive beings, allowing us to work together to solve problems, rather than tear each other to shreds.

5. Some of us have blue eyes.

Originally, we all had brown eyes. But about 10,000 years ago, someone who lived near the Black Sea developed a genetic mutation that turned brown eyes blue. While the reason blue eyes have persisted remains a bit of a mystery, one theory is that they act as a sort of paternity test. “There is strong evolutionary pressure for a man not to invest his paternal resources in another man’s child,” Bruno Laeng, lead author of a 2006 study on the development of blue eyes, told The New York Times. Because it is virtually impossible for two blue-eyed mates to create a brown-eyed baby, our blue-eyed male ancestors may have sought out blue-eyed mates as a way of ensuring fidelity. This would partially explain why, in a recent study, blue-eyed men rated blue-eyed women as more attractive compared to brown-eyed women, whereas females and brown-eyed men expressed no preference.

Now Ear This: A New App Can Detect a Child's Ear Infection

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iStock.com/Techin24

Generally speaking, using an internet connection to diagnose a medical condition is rarely recommended. But technology is getting better at outpacing skepticism over handheld devices guiding decisions and suggesting treatment relating to health care. The most recent example is an app that promises to identify one of the key symptoms of ear infections in kids.

The Associated Press reports that researchers at the University of Washington are close to finalizing an app that would allow a parent to assess whether or not their child has an ear infection using their phone, some paper, and some soft noises. A small piece of paper is folded into a funnel shape and inserted into the ear canal to focus the app's sounds (which resemble bird chirps) toward the child’s ear. The app measures sound waves bouncing off the eardrum. If pus or fluid is present, the sound waves will be altered, indicating a possible infection. The parent would then receive a text from the app notifying them of the presence of buildup in the middle ear.

The University of Washington tested the efficacy of the app by evaluating roughly 50 patients scheduled to undergo ear surgery at Seattle Children’s Hospital. The app was able to identify fluid in patients' ears about 85 percent of the time. That’s roughly as well as traditional exams, which involve visual identification as well as specialized acoustic devices.

While the system looks promising, not all cases of fluid in the ear are the result of infections or require medical attention. Parents would need to evaluate other symptoms, such as fever, if they intend to use the app to decide whether or not to seek medical attention. It may prove most beneficial in children with persistent fluid accumulation, a condition that needs to be monitored over the course of months when deciding whether a drain tube needs to be placed. Checking for fluid at home would save both time and money compared to repeated visits to a physician.

The app does not yet have Food and Drug Administration (FDA) approval and there is no timetable for when it might be commercially available. If it passes muster, it would join a number of FDA-approved “smart” medical diagnostic tools, including the AliveKor CardiaBand for the Apple Watch, which conducts EKG monitoring for heart irregularities.

[h/t WGRZ]

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