Posts tagged neuroscience
Articles and news from the latest research reports.
Learning dialects shapes brain areas that process spoken language
Using advanced imaging to visualize brain areas used for understanding language in native Japanese speakers, a new study from the RIKEN Brain Science Institute finds that the pitch-accent in words pronounced in standard Japanese activates different brain hemispheres depending on whether the listener speaks standard Japanese or one of the regional dialects.
In the study published in the journal Brain and Language, Drs. Yutaka Sato, Reiko Mazuka and their colleagues examined if speakers of a non-standard dialect used the same brain areas while listening to spoken words as native speakers of the standard dialect or as someone who acquired a second language later in life.
When we hear language our brain dissects the sounds to extract meaning. However, two people who speak the same language may have trouble understanding each other due to regional accents, such as Australian and American English. In some languages, such as Japanese, these regional differences are more pronounced than an accent and are called dialects.
Unlike different languages that may have major differences in grammar and vocabulary, the dialects of a language usually differ at the level of sounds and pronunciation. In Japan, in addition to the standard Japanese dialect, which uses a pitch-accent to distinguish identical words with different meanings, there are other regional dialects that do not.
Similar to the way that a stress in an English word can change its meaning, such as “pro’duce” and “produ’ce”, identical words in the standard Japanese language have different meanings depending on the pitch-accent. The syllables of a word can have either a high or a low pitch and the combination of pitch-accents for a particular word imparts it with different meanings.
The experimental task was designed to test the participants’ responses when they distinguish three types of word pairs: (1) words such as /ame’/ (candy) versus /kame/ (jar) that differ in one sound, (2) words such as /ame’/ (candy) versus /a’me/ (rain) that differ in their pitch accent, and (3) words such as ‘ame’ (candy in declarative intonation) and /ame?/ (candy in a question intonation).
RIKEN neuroscientists used Near Infrared Spectroscopy (NIRS) to examine whether the two brain hemispheres are activated differently in response to pitch changes embedded in a pair of words in standard and accent-less dialect speakers. This non-invasive way to visualize brain activity is based on the fact that when a brain area is active, blood supply increases locally in that area and this increase can be detected with an infrared laser.
It is known that pitch changes activate both hemispheres, whereas word meaning is preferentially associated with the left-hemisphere. When the participants heard the word pair that differed in pitch-accent, /ame’/ (candy) vs /a’me/ (rain), the left hemisphere was predominantly activated in standard dialect speakers, whereas in accent-less dialect speakers did not show the left-dominant activation. Thus, standard Japanese speakers use the pitch-accent to understand the word meaning. However, accent-less dialect speakers process pitch changes similar to individuals who learn a second language later in life.
The results are surprising because both groups are native Japanese speakers who are familiar with the standard dialect. “Our study reveals that an individual’s language experience at a young age can shape the way languages are processed in the brain,” comments Dr. Sato. “Sufficient exposure to a language at a young age may change the processing of a second language so that it is the same as that of the native language.”
Researchers make exciting discoveries in non-excitable cells
It has been 60 years since scientists discovered that sodium channels create the electrical impulses crucial to the function of nerve, brain, and heart cells — all of which are termed “excitable.” Now researchers at Yale and elsewhere are discovering that sodium channels also play key roles in so-called non-excitable cells.
In the Oct. 16 issue of the journal Neuron, Yale neuroscientists Stephen Waxman and Joel Black review nearly a quarter-century of research that shows sodium channels in cells that do not transmit electrical impulses may nonetheless play a role in immune system function, migration of cells, neurodegenerative disease, and cancer.
“This insight has opened up new avenues of research in a variety of pathologies,” Waxman said.
For instance, Waxman’s lab has begun to study the functional role of voltage-gated sodium channels in non-excitable glial cells within the spinal cord and brain. They are currently investigating whether sodium channels in these non-excitable cells may participate in the formation of glial scars, thereby inhibiting regeneration of nerve cells after traumatic injury to the spinal cord or brain.
Psychologists report new insights on human brain, consciousness
UCLA psychologists have used brain-imaging techniques to study what happens to the human brain when it slips into unconsciousness. Their research, published Oct. 17 in the online journal PLOS Computational Biology, is an initial step toward developing a scientific definition of consciousness.
"In terms of brain function, the difference between being conscious and unconscious is a bit like the difference between driving from Los Angeles to New York in a straight line versus having to cover the same route hopping on and off several buses that force you to take a ‘zig-zag’ route and stop in several places," said lead study author Martin Monti, an assistant professor of psychology and neurosurgery at UCLA.
Monti and his colleagues used functional magnetic resonance imaging (fMRI) to study how the flow of information in the brains of 12 healthy volunteers changed as they lost consciousness under anesthesia with propofol. The participants ranged in age from 18 to 31 and were evenly divided between men and women.
The psychologists analyzed the “network properties” of the subjects’ brains using a branch of mathematics known as graph theory, which is often used to study air-traffic patterns, information on the Internet and social groups, among other topics.
"It turns out that when we lose consciousness, the communication among areas of the brain becomes extremely inefficient, as if suddenly each area of the brain became very distant from every other, making it difficult for information to travel from one place to another," Monti said.
The finding shows that consciousness does not “live” in a particular place in our brain but rather “arises from the mode in which billions of neurons communicate with one another,” he said.
When patients suffer severe brain damage and enter a coma or a vegetative state, Monti said, it is very possible that the sustained damage impairs their normal brain function and the emergence of consciousness in the same manner as was seen by the life scientists in the healthy volunteers under anesthesia.
"If this were indeed the case, we could imagine in the future using our technique to monitor whether interventions are helping patients recover consciousness," he said.
"It could, however, also be the case that losing consciousness because of brain injury affects brain function through different mechanisms," said Monti, whose research team is currently addressing this question in another study.
"As profoundly defining of our mind as consciousness is, without having a scientific definition of this phenomenon, it is extremely difficult to study," Monti noted. This study, he said, marks an initial step toward conducting neuroscience research on consciousness.
The research was conducted at Belgium’s University Hospital of Liege.
Monti’s expertise includes cognitive neuroscience, the relationship between language and thought, and how consciousness is lost and recovered after severe brain injury. He was part of a team of American and Israeli brain scientists who used fMRI on former Israeli Prime Minister Ariel Sharon in January 2013 to assess his brain responses.
Surprisingly, Sharon, who was presumed to be in a vegetative state since suffering a brain hemorrhage in 2006, showed significant brain activity, Monti and his colleagues reported.
The former prime minister was scanned to assess the extent and quality of his brain processing, using methods recently developed by Monti and his colleagues. The scientists found subtle but encouraging signs of consciousness.
Two-legged Robots Learn to Walk like a Human
Teaching two-legged robots a stable, robust “human” way of walking – this is the goal of the international research project “KoroiBot” with scientists from seven institutions from Germany, France, Israel, Italy and the Netherlands. The experts from the areas of robotics, mathematics and cognitive sciences want to study human locomotion as exactly as possible and transfer this onto technical equipment with the assistance of new mathematical processes and algorithms. The European Union is financing the three-year research project that started in October 2013 with approx. EUR 4.16 million. The scientific coordinator is Prof. Dr. Katja Mombaur from Heidelberg University.
Whether as rescuers in disaster areas, household helps or as “colleagues” in modern work environments: there are numerous possible areas of deployment for humanoid robots in the future. “One of the major challenges on the way is to enable robots to move on two legs in different situations, without an accident – in spite of unknown terrain and also with possible disturbances,” explains Prof. Mombaur, who heads the working group “Optimisation in Robotics and Biomechanics” at Heidelberg University’s Interdisciplinary Center for Scientific Computing (IWR).
In the KoroiBot project the researchers will study the way humans walk e.g. on stairs and slopes, on soft and slippery ground or over beams and seesaws, and create mathematical models. Besides developing new optimisation and learning processes for walking on two legs, they aim to implement this in practice with existing robots. In addition, the research results are to flow into planning new design principles for the next generation of robots.
Besides Prof. Mombaur’s group, the working group “Simulation and Optimisation” is also involved in the project at the IWR. The Heidelberg scientists will investigate the way movement of humans and robots can be turned into mathematical models. Furthermore, the teams want to create optimised walking movements for different demands and develop new model-based control algorithms. Just under EUR 900,000 of the European Union funding is being channelled to Heidelberg.
Partners in the international consortium are, besides Heidelberg University, leading institutions in the field of robotics. These include the Karlsruhe Institute of Technology (KIT), the Centre National de la Recherche Scientifique (CNRS) with three laboratories, the Istituto Italiano di Tecnologia (IIT) and the Delft University of Technology in the Netherlands. Experts from the University of Tübingen and the Weizmann Institute of Science in Israel will contribute from the angle of cognitive sciences.
Besides the targeted use of robotics, the scientists expect possible applications in medicine, e.g. for controlling intelligent artificial limbs. They see further areas of application in designing and regulating exoskeletons as well as in computer animation and in game design.
(Source: uni-heidelberg.de)
Research finds brain scans may aid in diagnosis of autism
Joint research from the University of Alabama at Birmingham Department of Psychology and Auburn University indicates that brain scans show signs of autism that could eventually support behavior-based diagnosis of autism and effective early intervention therapies. The findings appear online today in Frontiers in Human Neuroscience as part of a special issue on brain connectivity in autism.
“This research suggests brain connectivity as a neural signature of autism and may eventually support clinical testing for autism,” said Rajesh Kana, Ph.D., associate professor of psychology and the project’s senior researcher. “We found the information transfer between brain areas, causal influence of one brain area on another, to be weaker in autism.”
The investigators found that brain connectivity data from 19 paths in brain scans predicted whether the participants had autism, with an accuracy rate of 95.9 percent.
Kana, working with a team including Gopikrishna Deshpande, Ph.D., from Auburn University’s MRI Research Center, studied 15 high-functioning adolescents and adults with autism, as well as 15 typically developing control participants ages 16-34 years. Kana’s team collected all data in his autism lab at UAB that was then analyzed using a novel connectivity method at Auburn.
The current study showed that adults with autism spectrum disorders processed social cues differently than typical controls. It also revealed the disrupted brain connectivity that explains their difficulty in understanding social processes.
“We can see that there are consistently weaker brain regions due to the disrupted brain connectivity,” Kana said. “There’s a very clear difference.”
Participants in this study were asked to choose the most logical of three possible endings as they watched a series of comic strip vignettes while a functional MRI scanner measured brain activity.
The scenes included a glass about to fall off a table and a man enjoying the music of a street violinist and giving him a cash tip. Most participants in the autism group had difficulty in finding a logical end to the violinist scenario, which required an understanding of emotional and mental states. The current study showed that adults with autism spectrum disorders struggle to process subtle social cues, and altered brain connectivity may underlie their difficulty in understanding social processes.
“We can see that the weaker connectivity hinders the cross-talk among brain regions in autism,” Kana said.
Kana plans to continue his research on autism.
“Over the next five to 10 years, our research is going in the direction of finding objective ways to supplement the diagnosis of autism with medical testing and testing the effectiveness of intervention in improving brain connectivity,” Kana said.
Autism is currently diagnosed through interviews and behavioral observation. Although autism can be diagnosed by 18 months, in reality, earliest diagnoses occur around ages 4-6 as children face challenges in school or social settings.
“Parents usually have a longer road before getting a firm diagnosis for their child now,” Kana said. “You lose a lot of intervention time, which is so critical. Brain imaging may not be able to replace the current diagnostic measures; but if it can supplement them at an earlier age, that’s going to be really helpful.”
(Source: uab.edu)
Keep your friends close, but …
Counterintuitive findings from a new USC study show that the part of the brain that is associated with empathizing with the pain of others is activated more strongly by watching the suffering of hateful people as opposed to likable people.
While one might assume that we would empathize more with people we like, the study may indicate that the human brain focuses more greatly on the need to monitor enemies closely, especially when they are suffering.
“When you watch an action movie and the bad guy appears to be defeated, the moment of his demise draws our focus intensely,” said Lisa Aziz-Zadeh of the Brain and Creativity Institute of the USC Dornsife College of Letters, Arts and Sciences. “We watch him closely to see whether he’s really down for the count because it’s critical for predicting his potential for retribution in the future.”
Aziz-Zadeh, who has a joint appointment with the USC Division of Occupational Science and Occupational Therapy, collaborated with lead author Glenn Fox, a PhD candidate at USC, and Mona Sobhani, formerly a graduate student at USC and who is now a postdoctoral researcher at Vanderbilt University, on a study that appears this month in Frontiers in Psychology.
The study examined activity in the so-called “pain matrix” of the brain, a network that includes the insula cortex, the anterior cingulate and the somatosensory cortices — regions known to activate when an individual watches another person suffer.
The pain matrix is thought to be a related to empathy — allowing us to understand another’s pain. However, this study indicates that the pain matrix may be more involved in processing pain in general and not necessarily tied to empathic processing.
Participants — all of them white, male and Jewish — first watched videos of hateful, anti-Semitic individuals in pain and then other videos of tolerant, nonhateful individuals in pain. Their brains were scanned with functional magnetic resonance imaging (fMRI) to show activity levels in the pain matrix.
Surprisingly, the participants’ pain matrices were more activated by watching the anti-Semites suffer compared to the tolerant individuals.
“The results further revealed the brain’s flexibility in processing complex social situations,” Fox said. “The brain uses the complete context of the situation to mount an appropriate response. In this case, the brain’s response is likely tied to the relative increase in the need to attend to and understand the pain of the hateful person.”
A possible next step for the researchers will be to try to understand how regulating one’s emotional reaction to stimuli such as these alters the resulting patterns of brain activity.
Scientists expand the genetic code of mammals to control protein activity in neurons with light
With the flick of a light switch, researchers at the Salk Institute for Biological Studies can change the shape of a protein in the brain of a mouse, turning on the protein at the precise moment they want. This allows the scientists to observe the exact effect of the protein’s activation. The new method, described in the Oct. 16, 2013, issue of the journal Neuron, relies on specially engineered amino acids—the molecules that make up proteins—and light from an LED. Now that it has been shown to work, the technique can be adapted to give researchers control of a wide variety of other proteins in the brain to study their functions.
"What we are now able to do is not only control neuronal activity, but control a specific protein within a neuron," says senior study author Lei Wang, an associate professor in Salk’s Jack H. Skirball Center for Chemical Biology and Proteomics and holder of the Frederick B. Rentschler Developmental Chair.
If a scientist wants to know what set of neurons in the brain is responsible for a particular action or behavior, being able to turn the neurons on and off at will gives the researcher a targeted way to test the neurons’ effects. Likewise, if they want to know the role of a certain protein inside the cells, the ability to activate or inactivate the protein of interest is key to studying its biology.
Over the past decade, researchers have developed a handful of ways of activating or inactivating neurons using light, as part of the burgeoning field of so-called optogenetics. In optogenetic experiments, mice are genetically engineered to have a light-sensitive channel from algae integrated into their neurons. When exposed to light, the channel opens or closes, changing the flow of molecules into the neuron and altering its ability to pass an electrochemical message through the brain. Using such optogenetic approaches, scientists can pick and choose which neurons in the brain they want turned on or off at any given time and observe the resulting change in the engineered mice.
"There’s no question that this is a great way to control neuronal activity, by borrowing light-responsive channels or pumps from other organisms and putting them in neurons," says Wang. "But rather than put a stranger into neurons, we wanted to control the activity of proteins native to neurons."
To make proteins respond to light, Wang’s team harnessed a photo-responsive amino acid, called Cmn, which has a large chemical structure. When a pulse of light shines on the molecule, Cmn’s bulky side chain breaks off, leaving cysteine, a smaller amino acid. Wang’s group realized that if a single Cmn was integrated into the right place in the structure of a protein, the drastic change in the amino acid’s size could activate or inactivate the entire protein.
To test their idea, Wang and his colleagues engineered new versions of a potassium channel in neurons, adding Cmn to their sequence.
"Basically the idea was that when you put this amino acid in the pore of the channel, the bulky side chain entirely blocks the passage of ions through the channel," explains Ji-Yong Kang, a graduate student who works in Wang’s group, and first author of the new paper. "Then, when the bond in the amino acid breaks in response to light, the channel is opened up."
The method worked in isolated cells: after trial and error, the scientists found the ideal spot in the channel to put Cmn, so that the channel was initially blocked, but opened when light shone on it. They were able to measure the change to the channel’s properties by recording the electrical current that flowed through the cells before and after exposure to light.
But to apply the technique to living mice, Wang and his colleagues needed to change the animals’ genetic code—the built-in instructions that cells use to produce proteins based on gene sequences. The normal genetic code doesn’t contain information on Cmn, so simply injecting Cmn amino acids into mice wouldn’t lead to the molecules being integrated into proteins. In the past, the Wang group and others have expanded the genetic codes of isolated cells of simple organisms like bacteria, or yeast, inserting instructions for a new amino acid. But the approach had never been successful in mammals. Through a combination of techniques and new tricks, however, Wang’s team was able to provide embryonic mice with the instructions for the new amino acid, Cmn. With the help from Salk Professor Dennis O’Leary and his research associate Daichi Kawaguchi, they then integrated the new Cmn-containing channel into the brains of the developing mice, and showed that by shining light on the brain tissue they could force the channel open, altering patterns of neuron activity. It was not only a first for expanding the genetic code of mammals, but also for protein control.
At the surface, the new approach has the same result as optogenetic approaches to studying the brain—neurons are silenced at a precise time in response to light. But Wang’s method can now be used to study a whole cadre of different proteins in neurons. Aside from being used to open and close channels or pores that let ions flow in and out of brain cells, Cmn could be used to optically regulate protein modifications and protein-protein interactions.
"We can pinpoint exactly which protein, or even which part of a protein, is crucial for the functioning of targeted neurons," says Wang. "If you want to study something like the mechanism of memory formation, it’s not always just a matter of finding what neurons are responsible, but what molecules within those neurons are critical."
Earlier this year, President Obama announced the multi-billion dollar Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative, a ten-year project to map the activity of the human brain. Creating new ways to study the molecules in the brain, such as using light-responsive amino acids to study neuronal proteins, will be key to moving forward on this initiative and similar efforts to understand the brain, says Wang. His lab is now working to develop ways to not only activate proteins, but inactive them using light-sensitive amino acids, and applying the technique to proteins other than Kir2.1.
Depression twice as likely in migraine sufferers
The prevalence of depression among those with migraine is approximately twice as high as for those without the disease (men: 8.4% vs. 3.4%; women 12.4% vs. 5.7%), according to a new study published by University of Toronto researchers.
In a paper published online this week in the journal Depression Research and Treatment, investigators reported that younger migraine sufferers were particularly at risk for depression. Women with migraines who were younger than 30 had six times the odds of depression in comparison to sufferers who were aged 65 and over, said lead author, Professor Esme Fuller-Thomson, Sandra Rotman Endowed Chair at the University of Toronto’s Factor-Inwentash Faculty of Social Work. Unmarried individuals and migraine sufferers who had difficulties with daily activities also had high odds of depression.
Data drawn from a representative sample of more than 67,000 Canadians, the 2005 Canadian Community Health Survey, were used to examine gender-specific associations between migraine and depression. More than 6,000 respondents reported that they had been diagnosed by a health professional with migraines. Consistent with prior research, the prevalence of migraines was much higher in women than men, with one in every seven women, compared to one in every 16 men, reporting that they had migraines.
The study also investigated the relationship between migraine and suicidal ideation. For both men and women, those with migraines were much more likely to have “ever seriously considered suicide or taking (their) own life” than were those without migraines (men: 15.6% versus 7.9%; women: 17.6% versus 9.1%). Migraineurs under age 30 had four times the odds of lifetime suicidal ideation in comparison to migraineurs aged 65 and over. Other factors associated with suicidal ideation among those with migraines included unmarried status, lower household income and greater activity limitations.
Co-author and former graduate student Meghan Schrumm commented “We are not sure why younger migraineurs have such a high likelihood of depression and suicidal ideation. It may be that younger people with migraines have not yet managed to find adequate treatment or develop coping mechanisms to minimize pain and the impact of this chronic illness on the rest of their lives. The much lower prevalence of depression and suicidal ideation among older migraineurs suggests a promising area for future research.”
Dr. Fuller-Thomson adds that this study “draws further attention to the need for routine screening and targeted interventions for depression and suicidality, particularly among the most vulnerable migraineurs: Individuals who are young, unmarried and those with activity limitations.”
(Image: Shutterstock)
Video could transform how schools serve teens with autism
Video-based teaching helps teens with autism learn important social skills, and the method eventually could be used widely by schools with limited resources, a Michigan State University researcher says.
The diagnosis rate for Autism Spectrum Disorder for 14- to 17-year-olds has more than doubled in the past five years, according to the Centers for Disease Control and Prevention. Yet previous research has found very few strategies for helping adolescents with autism develop skills needed to be successful, especially in group settings.
“Teaching social skills to adolescents with ASD has to be effective and practical,” said Joshua Plavnick, assistant professor of special education at MSU. “Using video-based group instruction regularly could promote far-reaching gains for students with ASD across many social behaviors.”
Plavnick developed group video teaching techniques with colleagues while a postdoctoral fellow at the University of North Carolina’s Frank Porter Graham Child Development Institute. Their findings are published in the research journal Exceptional Children.
Previous studies have shown many people with autism are more likely to pay attention when an innovative technology delivers information. Before Plavnick’s work, however, there were no investigations of video modeling as an option for teaching social skills to more than one adolescent with ASD at the same time.
The team recruited 13- to 17-year-old students with ASD and used laptops or iPads to offer group video instruction on social behaviors, such as inviting a peer to join an activity. One facilitator showed four students video footage of people helping one another clean up a mess, for example, and then gave them opportunities to practice the same skills in the classroom.
According to the researchers, the students demonstrated a rapid increase in the level of complex social behaviors each time video-based group instruction was used. Students sustained those social behaviors at high levels, even when the videos were used less often.
The students’ parents also completed anonymous surveys and indicated high levels of satisfaction. One reported their child started asking family members to play games together, a skill the teen had never before displayed at home.
Most schools do not have appropriate staff resources to provide one-on-one help for students with autism. The video can be used with a small group all at once and has been shown to be effective.
“Video-based group instruction is important, given the often limited resources in schools that also face increasing numbers of students being diagnosed with ASD,” said Plavnick, who also has begun implementing the strategy as part of a daily high school-based program.
(Source: msutoday.msu.edu)
Bird study finds key info about human speech-language development
A study led by Xiaoching Li, PhD, at the LSU Health Sciences Center New Orleans Neuroscience Center of Excellence, has shown for the first time how two tiny molecules regulate a gene implicated in speech and language impairments as well as autism disorders, and that social context of vocal behavior governs their function. The findings are published in the October 16, 2013 issue of The Journal of Neuroscience.
Speech and language impairments affect the lives of millions of people, but the underlying neural mechanisms are largely unknown and difficult to study in humans. Zebra finches learn to sing and use songs for social communications. Because the vocal learning process in birds has many similarities with speech and language development in humans, the zebra finch provides a useful model to study the neural mechanisms underlying speech and language in humans.
Mutations in the FOXP2 gene have been linked to speech and language deficits and in autism disorders. A current theory is that a precise amount of FOXP2 is required for the proper development of the neural circuits processing speech and language, so it is important to understand how the FOXP2 gene is regulated. In this study, the research team identified two microRNAs, or miRNAs, – miR-9 and miR-140-5p – that regulate the levels of FOXP2. (MicroRNAs are a new class of small RNA molecules that play an important regulatory role in cell biology. They prevent the production of a particular protein by binding to and destroying the messenger RNA that would have produced the protein.) The researchers showed that in the zebra finch brain, these miRNAs are expressed in a basal ganglia nucleus that is required for vocal learning, and their function is regulated during vocal learning. More intriguingly, the expression of these two miRNAs is also regulated by the social context of song behavior – in males singing undirected songs.
"Because the FOXP2 gene and these two miRNAs are evolutionarily conserved, the insights we obtained from studying birds are highly relevant to speech and language in humans and related neural developmental disorders such as autism," notes Xiaoching Li, PhD,
LSUHSC Assistant Professor of Cell Biology and Anatomy as well as Neuroscience. “Understanding how miRNAs regulate FOXP2 may open many possibilities to influence speech and language development through genetic variations in miRNA genes, as well as behavioral and environmental factors.”
