Months before their first words, babies’ brains rehearse speech mechanics

Infants can tell the difference between sounds of all languages until about 8 months of age when their brains start to focus only on the sounds they hear around them. It’s been unclear how this transition occurs, but social interactions and caregivers’ use of exaggerated “parentese” style of speech seem to help.

University of Washington research in 7- and 11-month-old infants shows that speech sounds stimulate areas of the brain that coordinate and plan motor movements for speech.

The study, published July 14 in the Proceedings of the National Academy of Sciences, suggests that baby brains start laying down the groundwork of how to form words long before they actually begin to speak, and this may affect the developmental transition.

“Most babies babble by 7 months, but don’t utter their first words until after their first birthdays,” said lead author Patricia Kuhl, who is the co-director of the UW’s Institute for Learning and Brain Sciences. “Finding activation in motor areas of the brain when infants are simply listening is significant, because it means the baby brain is engaged in trying to talk back right from the start and suggests that 7-month-olds’ brains are already trying to figure out how to make the right movements that will produce words.”

Kuhl and her research team believe this practice at motor planning contributes to the transition when infants become more sensitive to their native language.

The results emphasize the importance of talking to kids during social interactions even if they aren’t talking back yet.

“Hearing us talk exercises the action areas of infants’ brains, going beyond what we thought happens when we talk to them,” Kuhl said. “Infants’ brains are preparing them to act on the world by practicing how to speak before they actually say a word.”

In the experiment, infants sat in a brain scanner that measures brain activation through a noninvasive technique called magnetoencephalography. Nicknamed MEG, the brain scanner resembles an egg-shaped vintage hair dryer and is completely safe for infants. The Institute for Learning and Brain Sciences was the first in the world to use such a tool to study babies while they engaged in a task.

The babies, 57 7- and 11- or 12-month-olds, each listened to a series of native and foreign language syllables such as “da” and “ta” as researchers recorded brain responses. They listened to sounds in English and in Spanish.

The researchers observed brain activity in an auditory area of the brain called the superior temporal gyrus, as well as in Broca’s area and the cerebellum, cortical regions responsible for planning the motor movements required for producing speech.

This pattern of brain activation occurred for sounds in the 7-month-olds’ native language (English) as well as in a non-native language (Spanish), showing that at this early age infants are responding to all speech sounds, whether or not they have heard the sounds before.

In the older infants, brain activation was different. By 11-12 months, infants’ brains increase motor activation to the non-native speech sounds relative to native speech, which the researchers interpret as showing that it takes more effort for the baby brain to predict which movements create non-native speech. This reflects an effect of experience between 7 and 11 months, and suggests that activation in motor brain areas is contributing to the transition in early speech perception.

The study has social implications, suggesting that the slow and exaggerated parentese speech – “Hiiiii! How are youuuuu?” – may actually prompt infants to try to synthesize utterances themselves and imitate what they heard, uttering something like “Ahhh bah bah baaah.”

“Parentese is very exaggerated, and when infants hear it, their brains may find it easier to model the motor movements necessary to speak,” Kuhl said.

Beneath the Surface: What Zebrafish Can Tell Us About Anxiety

The right tool for the job is important. A surgeon wouldn’t use a chainsaw when a scalpel offers more control. But sometimes the best treatments available aren’t precise. For example, anxiety medications available today are too blunt in how they target the brain, according to Ian Woods, assistant professor of biochemistry at Ithaca College.

“If you look at current treatments for anxiety disorders, the approach is a bit like taking a sledgehammer to a mosquito,” he said. “The treatments may work for anxiety, but they can have a lot of side effects.”

Woods researches how genetics influence responses to stimuli that can trigger anxiety, and he’s using zebrafish — a tropical member of the minnow family named for the black stripes on their bodies — to do so. He and his team of student researchers examine how fish with tweaked genes respond to different triggers compared to unmodified fish. The work could someday lead to better, more nuanced medications for anxiety disorders.

Zebrafish make ideal test subjects for several reasons. The embryos are transparent and develop outside the mother’s body, making it easy for Woods and his team to observe their growth under a microscope. They develop rapidly, are easy to care for and easy to breed in large quantities.

Specifically, Woods is looking at neuropeptides, which are the chemical messengers between brain cells. Different neuropeptides deliver different messages, which in turn produce different behaviors.

“Fish have the same neuropeptides as humans, and they mostly do the same things in the brain,” Woods said. “We can never faithfully model a complex human behavior like anxiety, but when we’re trying to figure out how the brain works, it’s useful to see inside a fish.”

Woods and his team isolate specific genes to disrupt, amplify, alter or replace, then analyze the movements of the modified fish with the aid of a computerized camera system. They examine responses to stimuli such as slight changes in water temperature, decreases in light intensity, or mild chemical irritants such as mustard oil.

“By observing the ensuing behavioral changes in the fish, we know how that replaced gene changed the message in the brain,” Woods explained. For example, fish exhibiting anxiety-like behaviors might hug the walls of the tank, while the rest will swim toward the middle. It’s not unlike social experiments in which the room temperature is raised gradually to see how human occupants will react.

“Genes typically don’t cause the anxiety,” Woods said. “But they can make organisms more susceptible to environmental triggers that might elicit what we’d call an anxious behavior.”

Anxiety disorders are the most common mental illness in the United States; over 40 million Americans suffer from some type in their lifetimes. But medications can be overprescribed and abused. For example, emergency room visits related to the use of Xanax and related drugs doubled from 2005 to 2011, according to the U.S. Substance Abuse and Mental Health Services Administration.

Can Games, Puzzles Keep Aging Minds Sharp?

Older adults who enjoy mentally stimulating games may have bigger brains and sharper thinking skills than their peers, new research suggests.

The study looked at the connection between playing games such as puzzles, crosswords, cards and checkers and mental acuity for adults in their 50s and 60s.

Researchers found that people who played those games at least every other day performed better on tests of memory and other mental functions. And, based on MRI scans, they had greater tissue mass in brain areas involved in memory.

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(Image: Alamy)

US Alzheimer’s Rate Seems to Be Dropping

The rate of Alzheimer’s disease and other dementias is falling in the United States and some other rich countries — good news about an epidemic that is still growing simply because more people are living to an old age, new studies show.

An American over age 60 today has a 44 percent lower chance of developing dementia than a similar-aged person did roughly 30 years ago, the longest study of these trends in the U.S. concluded.

Dementia rates also are down in Germany, a study there found.

"For an individual, the actual risk of dementia seems to have declined," probably due to more education and control of health factors such as cholesterol and blood pressure, said Dr. Kenneth Langa. He is a University of Michigan expert on aging who discussed the studies Tuesday at the Alzheimer’s Association International Conference in Copenhagen.

The opposite is occurring in some poor countries that have lagged on education and health, where dementia seems to be rising.

More than 5.4 million Americans and 35 million people worldwide have Alzheimer’s, the most common form of dementia. It has no cure and current drugs only temporarily ease symptoms.

A drop in rates is a silver lining in the so-called silver tsunami — the expected wave of age-related health problems from an older population. Alzheimer’s will remain a major public health issue, but countries where rates are dropping may be able to lower current projections for spending and needed services, experts said.

Recent studies from the Netherlands, Sweden and England have suggested a decline, and the new research extends this look to some other parts of the world.

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Smell and eye tests show potential to detect Alzheimer’s early

A decreased ability to identify odors might indicate the development of cognitive impairment and Alzheimer’s disease, while examinations of the eye could indicate the build-up of beta-amyloid, a protein associated with Alzheimer’s, in the brain, according to the results of four research trials reported today at the Alzheimer’s Association International Conference® 2014 (AAIC® 2014) in Copenhagen.

In two of the studies, the decreased ability to identify odors was significantly associated with loss of brain cell function and progression to Alzheimer’s disease. In two other studies, the level of beta-amyloid detected in the eye (a) was significantly correlated with the burden of beta-amyloid in the brain and (b) allowed researchers to accurately identify the people with Alzheimer’s in the studies.

Beta-amyloid protein is the primary material found in the sticky brain “plaques” characteristic of Alzheimer’s disease. It is known to build up in the brain many years before typical Alzheimer’s symptoms of memory loss and other cognitive problems.

"In the face of the growing worldwide Alzheimer’s disease epidemic, there is a pressing need for simple, less invasive diagnostic tests that will identify the risk of Alzheimer’s much earlier in the disease process," said Heather Snyder, Ph.D., Alzheimer’s Association director of Medical and Scientific Operations. "This is especially true as Alzheimer’s researchers move treatment and prevention trials earlier in the course of the disease."

"More research is needed in the very promising area of Alzheimer’s biomarkers because early detection is essential for early intervention and prevention, when new treatments become available. For now, these four studies reported at AAIC point to possible methods of early detection in a research setting to choose study populations for clinical trials of Alzheimer’s treatments and preventions," Snyder said.

With the support of the Alzheimer’s Association and the Alzheimer’s community, the United States created its first National Plan to Address Alzheimer’s Disease in 2012. The plan includes the critical goal, which was adopted by the G8 at the Dementia Summit in 2013, of preventing and effectively treating Alzheimer’s by 2025. It is only through strong implementation and adequate funding of the plan, including an additional $200 million in fiscal year 2015 for Alzheimer’s research, that we’ll meet that goal. For more information and to get involved, visit http://www.alz.org.

Clinically, at this time it is only possible to detect Alzheimer’s late in its development, when significant brain damage has already occurred. Biological markers of Alzheimer’s disease may be able to detect it at an earlier stage. For example, using brain PET imaging in conjunction with a specialized chemical that binds to beta-amyloid protein, the buildup of the protein as plaques in the brain can be revealed years before symptoms appear. These scans can be expensive and are not available everywhere. Amyloid can also be detected in cerebrospinal fluid through a lumbar puncture where a needle is inserted between two bones (vertebrae) in your lower back to remove a sample of the fluid that surrounds your brain and spinal cord.

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Molecular imbalance linked to brain tumour seizures

Researchers in France may have discovered why some patients with a type of brain tumour have epileptic seizures.

“This small study is interesting and shows that glioma-linked epilepsy may be connected to certain channels found in the membranes of nerve cells” - Dr Robin Grant, Edinburgh Cancer Research UK Centre

Their study, published in Science Translational Medicine, suggests that seizures in patients with glioma may be linked to an imbalance of chloride – which is involved in nerve activity – in certain brain cells.

Whether a patient has seizures is linked to how aggressive their tumour is – with less aggressive cases being more prone to epilepsy as tumour cells slowly progress and alter brain tissue.

It is hoped that further research could explore treatments for glioma-linked epilepsy by controlling chloride levels in the brain.

Glioma develops from specialised brain cells known as ‘glial cells’ that usually help to keep brain nerve cells in place, providing support and protection to ensure correct brain function.

In the latest study, scientists from Sorbonne University studied brain tissue samples from 47 glioma patients and found that nerve tissue infiltrated by glioma cells behaves in similar ways to other forms of epilepsy.

Looking at the patient samples, the team found that a particular type of nerve cell – called a pyramidal cell – released excessive amounts of chloride from inside the cells when exposed to a molecule called GABA, which is also involved in transmitting nerve signals.

GABA was released by other neighbouring nerve cells called ‘interneurons’. And the researchers believe that the release of chloride through specialised molecular channels in the membrane of nerve cells, may be responsible for the seizures experienced in some glioma patients.

Dr Robin Grant, an expert in epilepsy and glioma from the Edinburgh Cancer Research UK Centre, who was not involved in the research, said that the channels may make good drug targets for further investigation, but a finer understanding of the involvement of other processes is still needed.

“This small study is interesting and shows that glioma-linked epilepsy, as with other types of epilepsy, may be connected to certain channels found in the membranes of nerve cells.

“More research will be needed to understand the finer details of this process in glioma and whether these channels, along with other similar channels found in nerve cells, could be good targets for drugs to help control the condition.”

Virtual Finger Enables Scientists to Navigate and Analyze 3D Images of Complex Biological Structures

Researchers have pioneered a revolutionary new way to digitally navigate three-dimensional images. The new technology, called Virtual Finger, allows scientists to move through digital images of small structures like neurons and synapses using the flat surface of their computer screens. Virtual Finger’s unique technology makes 3D imaging studies orders of magnitude more efficient, saving time, money and resources at an unprecedented level across many areas of experimental biology. The software and its applications are profiled in this week’s issue of the journal Nature Communications.

Most other image analysis software works by dividing a three-dimensional image into a series of thin slices, each of which can be viewed like a flat image on a computer screen. To study three-dimensional structures, scientists sift through the slices one at a time: a technique that is increasingly challenging with the advent of big data. “Looking through 3D image data one flat slice at a time is simply not efficient, especially when we are dealing with terabytes of data,” explains Hanchuan Peng, Associate Investigator at the Allen Institute for Brain Science. “This is similar to looking through a glass window and seeing objects outside, but not being able to manipulate them because of the physical barrier.”

In sharp contrast, Virtual Finger allows scientists to digitally reach into three-dimensional images of small objects like single cells to access the information they need much more quickly and intuitively. “When you move your cursor along the flat screen of your computer, our software recognizes whether you are pointing to an object that is near, far, or somewhere in between, and allows you to analyze it in depth without having to sift through many two-dimensional images to reach it,” explains Peng.

Scientists at the Allen Institute are already using Virtual Finger to improve their detection of spikes from individual cells, and to better model the morphological structures of neurons. But Virtual Finger promises to be a game-changer for many biological experiments and methods of data analysis, even beyond neuroscience. In their Nature Communications article, the collaborative group of scientists describes how the technology has already been applied to perform three-dimensional microsurgery in order to knock out single cells, study the developing lung, and create a map of all the neural connections in the fly brain.

“Using Virtual Finger could make data collection and analysis ten to 100 times faster, depending on the experiment,” says Peng. “The software allows us to navigate large amounts of biological data in the same way that Google Earth allows you to navigate the world. It truly is a revolutionary technology for many different applications within biological science,” says Peng.

Hanchuan Peng began developing Virtual Finger while at the Howard Hughes Medical Institute’s Janelia Research Campus and continued development at the Allen Institute for Brain Science.