Posts tagged neuroimaging
Articles and news from the latest research reports.
New technique for deep brain stimulation surgery proves accurate and safe
Surgery has been used for Parkinson’s disease and familial tremors, and also shows promise for other disorders
The surgeon who more than two decades ago pioneered deep brain stimulation surgery in the United States to treat people with Parkinson’s disease and other movement disorders has now developed a new way to perform the surgery — which allows for more accurate placement of the brain electrodes and likely is safer for patients.
The success and safety of the new surgical technique could have broad implications for deep brain stimulation, or DBS, surgery into the future, as it may increasingly be used to help with a wide range of medical issues beyond Parkinson’s disease and familial tremors.
The new surgery also offers another distinct advantage: patients are asleep during the surgery, rather than being awake under local anesthesia to help surgeons determine placement of the electrodes as happens with the traditional DBS surgery.
A study detailing the new surgical technique is being published in the June 2013 edition of the Journal of Neurosurgery, and has been published online at the journal’s website.
"I think this will be how DBS surgery will be done in most cases going forward," said Kim Burchiel, M.D., F.A.C.S., chair of neurological surgery at Oregon Health & Science University and the lead author of the Journal of Neurosurgery article. “This surgery allows for extremely accurate placement of the electrodes and it’s safer. Plus patients don’t need to be awake during this surgery — which will mean many more patients who can be helped by this surgery will now be willing to consider it.”
DBS surgery was first developed in France in 1987. Burchiel was the first surgeon in North America to perform the surgery, as part of a Food and Drug Administration-approved clinical trial in 1991.
The FDA approved the surgery for “essential tremor” in 1997 and for tremors associated with Parkinson’s disease in 2002. The surgery has been performed tens of thousands of times over the last decade or so in the United States, most often for familial tremor and Parkinson’s disease. Burchiel and his team at OHSU have performed the surgery more than 750 times.
The surgery involves implanting very thin wire electrodes in the brain, connected to something like a pacemaker implanted in the chest. The system then stimulates the brain to often significantly reduce the tremors.
For most of the last two decades, the DBS patient was required to be awake during surgery, to allow surgeons to determine through monitoring the patient’s symptoms and getting other conscious patient feedback whether the electrodes were placed in the right spots in the brain.
But the traditional form of the surgery had drawbacks. Many patients who might have benefitted weren’t willing to undergo the sometimes 4 to 6 hour surgery while awake. There also is a small chance of hemorrhaging in the brain as the surgeon places or moves the electrodes to the right spot in the brain.
The new technique uses advances in brain imaging in recent years to place the electrodes more safely, and more accurately, than in traditional DBS surgery. The surgical team uses CT scanning during the surgery itself, along with an MRI of the patient’s brain before the surgery, to precisely place the electrodes in the brain, while better ensuring no hemorrhaging or complications from the insertion of the electrode.
The Journal of Neurosurgery article reported on 60 patients who had the surgery at OHSU over an 18-month period beginning in early 2011.
"What our results say is that it’s safe, that we had no hemorrhaging or complications at all — and the accuracy of the electrode placement is the best ever reported," Burchiel said.
Burchiel and his team have done another 140 or so surgeries with the new procedure since enrollment in the study ended. OHSU was the first center to pioneer the new DBS procedure, but other surgical teams across the U.S. are learning the technique at OHSU, and bringing it back to their own centers.
The positive results with the new DBS technique could have ramifications as medical researchers nationwide continue to explore possible new uses for DBS surgery. DBS surgery has shown promising results in clinical trials with some Alzheimer’s patients, with some forms of depression and even with obesity.
If the early promising results for these conditions are confirmed, the number of people who might be candidates for DBS surgery could expand greatly, Burchiel said.
The length of the new surgery for the 60 patients involved in the study was slightly longer than traditional DBS surgery. But as Burchiel and his team have developed the new surgical technique, the new DBS surgeries are usually much shorter, often taking half the time of the more traditional approach. Given that, and that the electrodes are placed more accurately and the surgery is cheaper to perform, the new DBS surgery likely will be the technique most surgeons will use in coming years, Burchiel said.
DBS surgery often helps significantly reduce tremors in patients with familial tremor and tremors and other symptoms in Parkinson’s disease. A parallel study is ongoing at OHSU to assess how symptoms of the patients have improved since their DBS surgery using this new method.
(Image: Dr Frank Gaillard)
Fear: A Justified Response or Faulty Wiring?
Fear is one of the most primal feelings known to man and beast. As we develop in society and learn, fear is hard coded into our neural circuitry through the amygdala, a small, almond-shaped nuclei of neurons within the medial temporal lobe of the brain. For psychologists and neurologists, the amygdala is a particularly interesting region of the brain because it plays a role in emotional learning and can have profound effects on human and animal behavior.
On June 3, 2013, a new article studying amygdala activity in human beings will be published as part of JoVE Behavior, a new section of the video journal that focuses on the behavioral sciences. The technique, developed by Dr. Fred Helmstetter and his research group at the University of Wisconsin-Milwaukee, studies how the brain responds to anticipated painful stimuli, in this case an electric shock, in volunteer test subjects.
“We’re interested in how the brain reacts to stimuli in the environment and how it changes when we form a memory of what we experience.” Dr. Helmstetter explains. “The amygdala is a part of the brain that’s important for the way we determine what is dangerous and what is safe around us and how we react to threat. This experiment is novel in that we are able to look at activity in the amygdala on a very detailed time scale while it responds to human faces.“
The technique takes advantage of two neuroimaging techniques: magnetic resonance imaging and magnetoencephalography. Magnetic resonance imaging (MRI) is a method where a test subject’s brain can be imaged in high resolution while the test subject is immobilized, creating a map of the brain. Once this map has been obtained, magnetoencephalography (MEG) is used to record the magnetic fields created by the electrical activity within the brain. When the test subject is shocked, or anticipates a shock, amygdala activity is picked up by the MEG and mapped to the MRI computer model.
As an emotional control center in the brain, the amygdala serves as a key component in a line of neurological structures that identify and respond to perceived threat. Dr. Helmstetter tells us, “There is good evidence to suggest that anxiety disorders and other psychopathology might be directly related to altered functioning of the amygdala. Prior work with other non-invasive imaging modalities supports this idea but has only been able to average the results of neural activity over several seconds which results in a poor picture of how neurons react to a stimulus over time. This work represents a significant improvement and will allow new questions to be answered.”
The article is part of the launch of JoVE Behavior, the eighth section of JoVE. Founded in 2006, JoVE has rapidly expanded its scope from general biology to many disciplines by visualizing experimentation. Director of Content Aaron Kolski-Andreaco, PhD explains that, “By dedicating a section to behavior, JoVE has provided a platform for researchers to visualize experiments aimed at answering questions about how we think, feel, and communicate with one another. Emphasizing this area of science is the next logical step for our journal, as the multidisciplinary study of behavior is enabled by technological advancements in physics, chemistry, and the life sciences - areas JoVE has already covered.”
Research Shows How Ritalin Affects Brains of Kids With ADHD
Ritalin activates specific areas of the brain in children with attention-deficit/hyperactivity disorder (ADHD), mimicking the brain activity of children without the condition, a new review says.
"This suggests that Ritalin does bring the brain [of a child with ADHD] back to the brain the typically developing kid has," said study author Constance Moore, associate director of the translational center for comparative neuroimaging at the University of Massachusetts Medical School.
Analyzing data from earlier studies that looked at how children’s brains were affected by doing certain tasks that are sometimes challenging for kids with ADHD, the researchers found that Ritalin (methylphenidate) was having a visible impact on three areas of the brain known to be associated with ADHD: the cortex, the cerebellum and the basal ganglia.
The study could be helpful in diagnosing and treating children with ADHD, Moore said. “It may be helpful to know that in certain children, Ritalin is having a physiological effect in the areas of the brain involved with attention and impulse control,” she said.
The research was published recently in the Harvard Review of Psychiatry.
Nine studies analyzed by the researchers used functional MRI to evaluate brain changes after children had taken a single dose of Ritalin. The children were involved in different types of tasks that tested their ability to focus and inhibit an impulse to act.
For example, to observe the brain’s reaction during a test of what is called “inhibitory control,” a child was told that every time he saw a zero show up on a screen, he should push the button on the right; every time he saw an X appear, he should push the left button. The children would then be asked to flip their responses, pushing the left button when they saw a zero.
"That’s hard to do," Moore said, "because you’ve developed the habit [of pushing the other button], so you have to suppress your impulse. If you do 20 zeros and keep pressing and then you see an X, most kids with ADHD will hit the wrong button."
In three out of five of the inhibitory control studies, Ritalin at least partially normalized brain activation in ADHD children.
To note how the brain reacted to a selective attention test, Moore said, children would first be asked, for example, what word they were seeing. The word would be “red,” and the color of the type also would be red. Then they would be shown the word “red,” but the color of the type would be green. In several studies, Ritalin affected activation in the frontal lobes during such inhibitory control tasks.
Most of the studies included in the review were performed in the United States or the United Kingdom. The majority of participants were adolescent boys, and all studies compared their results to healthy children of the same approximate age.
Because none of the studies looked at the correlation between ADHD symptoms and whether the child was taking Ritalin, there is no way to link the changes in brain activation with clinical improvement, Moore said. “It’s possible that kids who are not responsive to Ritalin may have brain changes too,” she said.
ADHD affects between 3 percent and 7 percent of school-aged children in the United States, according to the American Psychiatric Association. Boys are more likely to have ADHD than girls.
One expert was not surprised by the results.
"The review article shows there is a consensus of well-designed imaging studies showing that [Ritalin] has an impact on the frontal cortex of the brain, where we have long believed these patients have issues," said Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at the Steven & Alexandra Cohen Children’s Medical Center of New York, in New Hyde Park. Adesman wondered if Ritalin may play a role in helping the brain mature.
"Their data provides partial support for that," he said. "But if anything, the medicine seems to help the brain look more normal and doesn’t seem to do anything bad to it."
(Source: consumer.healthday.com)
Neuroscientists get yes-no answers via brain activity
Western researchers have used neuroimaging to read human thought via brain activity when they are conveying specific ‘yes’ or ‘no’ answers.
Their findings were published today in The Journal of Neuroscience in a study titled, The Brain’s Silent Messenger: Using Selective Attention to Decode Human Thought for Brain-Based Communication.
According to lead researcher Lorina Naci, the interpretation of human thought from brain activity – without depending on speech or action – is one of the most provoking and challenging frontiers of modern neuroscience. Specifically, patients who are fully conscious and awake, yet, due to brain damage, are unable to show any behavioral responsivity, expose the limits of the neuromuscular system and the necessity for alternate forms of communication.
Participants were asked to concentrate on a ‘yes’ or ‘no’ response to questions like “Are you married?” or “Do you have brothers and sisters?” and only think their response, not speak it.
“This novel method allowed healthy individuals to answers questions asked in the scanner, simply by paying attention to the word they wanted to convey. By looking at their brain activity we were able to correctly decode the correct answers for each individual,” said Naci, a postdoctoral fellow at Western’s Brain and Mind Institute. “The majority of volunteers conveyed their answers within three minutes of scanning, a time window that is well-suited for communication with brain-computer interfaces.”
Naci and her Western colleagues Rhodri Cusack, Vivian Z. Jia and Adrian Owen are now utilizing this method to communicate with behaviorally non-responsive patients, who may be misdiagnosed as being in a vegetative state.
“The strengths of this technique, especially its ease of use, robustness, and rapid detection, may maximize the chances that any such patient will be able to achieve brain-based communication,” Naci said.
Changing gut bacteria through diet affects brain function
UCLA researchers now have the first evidence that bacteria ingested in food can affect brain function in humans. In an early proof-of-concept study of healthy women, they found that women who regularly consumed beneficial bacteria known as probiotics through yogurt showed altered brain function, both while in a resting state and in response to an emotion-recognition task.
The study, conducted by scientists with UCLA’s Gail and Gerald Oppenheimer Family Center for Neurobiology of Stress and the Ahmanson–Lovelace Brain Mapping Center at UCLA, appears in the current online edition of the peer-reviewed journal Gastroenterology.
The discovery that changing the bacterial environment, or microbiota, in the gut can affect the brain carries significant implications for future research that could point the way toward dietary or drug interventions to improve brain function, the researchers said.
"Many of us have a container of yogurt in our refrigerator that we may eat for enjoyment, for calcium or because we think it might help our health in other ways," said Dr. Kirsten Tillisch, an associate professor of medicine at UCLA’s David Geffen School of Medicine and lead author of the study. "Our findings indicate that some of the contents of yogurt may actually change the way our brain responds to the environment. When we consider the implications of this work, the old sayings ‘you are what you eat’ and ‘gut feelings’ take on new meaning."
Researchers have known that the brain sends signals to the gut, which is why stress and other emotions can contribute to gastrointestinal symptoms. This study shows what has been suspected but until now had been proved only in animal studies: that signals travel the opposite way as well.
"Time and time again, we hear from patients that they never felt depressed or anxious until they started experiencing problems with their gut," Tillisch said. "Our study shows that the gut–brain connection is a two-way street."
The small study involved 36 women between the ages of 18 and 55. Researchers divided the women into three groups: one group ate a specific yogurt containing a mix of several probiotics — bacteria thought to have a positive effect on the intestines — twice a day for four weeks; another group consumed a dairy product that looked and tasted like the yogurt but contained no probiotics; and a third group ate no product at all.
Functional magnetic resonance imaging (fMRI) scans conducted both before and after the four-week study period looked at the women’s brains in a state of rest and in response to an emotion-recognition task in which they viewed a series of pictures of people with angry or frightened faces and matched them to other faces showing the same emotions. This task, designed to measure the engagement of affective and cognitive brain regions in response to a visual stimulus, was chosen because previous research in animals had linked changes in gut flora to changes in affective behaviors.
The researchers found that, compared with the women who didn’t consume the probiotic yogurt, those who did showed a decrease in activity in both the insula — which processes and integrates internal body sensations, like those form the gut — and the somatosensory cortex during the emotional reactivity task.
Further, in response to the task, these women had a decrease in the engagement of a widespread network in the brain that includes emotion-, cognition- and sensory-related areas. The women in the other two groups showed a stable or increased activity in this network.
During the resting brain scan, the women consuming probiotics showed greater connectivity between a key brainstem region known as the periaqueductal grey and cognition-associated areas of the prefrontal cortex. The women who ate no product at all, on the other hand, showed greater connectivity of the periaqueductal grey to emotion- and sensation-related regions, while the group consuming the non-probiotic dairy product showed results in between.
The researchers were surprised to find that the brain effects could be seen in many areas, including those involved in sensory processing and not merely those associated with emotion, Tillisch said.
The knowledge that signals are sent from the intestine to the brain and that they can be modulated by a dietary change is likely to lead to an expansion of research aimed at finding new strategies to prevent or treat digestive, mental and neurological disorders, said Dr. Emeran Mayer, a professor of medicine, physiology and psychiatry at the David Geffen School of Medicine at UCLA and the study’s senior author.
"There are studies showing that what we eat can alter the composition and products of the gut flora — in particular, that people with high-vegetable, fiber-based diets have a different composition of their microbiota, or gut environment, than people who eat the more typical Western diet that is high in fat and carbohydrates," Mayer said. "Now we know that this has an effect not only on the metabolism but also affects brain function."
The UCLA researchers are seeking to pinpoint particular chemicals produced by gut bacteria that may be triggering the signals to the brain. They also plan to study whether people with gastrointestinal symptoms such as bloating, abdominal pain and altered bowel movements have improvements in their digestive symptoms which correlate with changes in brain response.
Meanwhile, Mayer notes that other researchers are studying the potential benefits of certain probiotics in yogurts on mood symptoms such as anxiety. He said that other nutritional strategies may also be found to be beneficial.
By demonstrating the brain effects of probiotics, the study also raises the question of whether repeated courses of antibiotics can affect the brain, as some have speculated. Antibiotics are used extensively in neonatal intensive care units and in childhood respiratory tract infections, and such suppression of the normal microbiota may have long-term consequences on brain development.
Finally, as the complexity of the gut flora and its effect on the brain is better understood, researchers may find ways to manipulate the intestinal contents to treat chronic pain conditions or other brain related diseases, including, potentially, Parkinson’s disease, Alzheimer’s disease and autism.
Answers will be easier to come by in the near future as the declining cost of profiling a person’s microbiota renders such tests more routine, Mayer said.
Chronic trauma can inflict lasting damage to brain regions associated with fear and anxiety. Previous imaging studies of people with post-traumatic stress disorder, or PTSD, have shown that these brain regions can over-or under-react in response to stressful tasks, such as recalling a traumatic event or reacting to a photo of a threatening face. Now, researchers at NYU School of Medicine have explored for the first time what happens in the brains of combat veterans with PTSD in the absence of external triggers.
Their results, published in Neuroscience Letters, and presented today at the annual meeting of the American Psychiatry Association in San Francisco, show that the effects of trauma persist in certain brain regions even when combat veterans are not engaged in cognitive or emotional tasks, and face no immediate external threats. The findings shed light on which areas of the brain provoke traumatic symptoms and represent a critical step toward better diagnostics and treatments for PTSD.
A chronic condition that develops after trauma, PTSD can plague victims with disturbing memories, flashbacks, nightmares and emotional instability. Among the 1.7 million men and women who have served in the wars in Iraq and Afghanistan, an estimated 20% have PTSD. Research shows that suicide risk is higher in veterans with PTSD. Tragically, more soldiers committed suicide in 2012 than the number of soldiers who were killed in combat in Afghanistan that year.
"It is critical to have an objective test to confirm PTSD diagnosis as self reports can be unreliable," says co-author Charles Marmar, MD, the Lucius N. Littauer Professor of Psychiatry and chair of NYU Langone’s Department of Psychiatry. Dr. Marmar, a nationally recognized expert on trauma and stress among veterans, heads The Steven and Alexandra Cohen Veterans Center for the Study of Post-Traumatic Stress and Traumatic Brain Injury at NYU Langone Medical Center.
The study, led by Xiaodan Yan, a research fellow at NYU School of Medicine, examined “spontaneous” or “resting” brain activity in 104 veterans of combat from the Iraq and Afghanistan wars using functional MRI, which measures blood-oxygen levels in the brain. The researchers found that spontaneous brain activity in the amygdala, a key structure in the brain’s “fear circuitry” that processes fearful and anxious emotions, was significantly higher in the 52 combat veterans with PTSD than in the 52 combat veterans without PTSD. The PTSD group also showed elevated brain activity in the anterior insula, a brain region that regulates sensitivity to pain and negative emotions.
Moreover, the PTSD group had lower activity in the precuneus, a structure tucked between the brain’s two hemispheres that helps integrate information from the past and future, especially when the mind is wandering or disengaged from active thought. Decreased activity in the precuneus correlates with more severe “re-experiencing” symptoms—that is, when victims re-experience trauma over and over again through flashbacks, nightmares and frightening thoughts.
Alzheimer’s markers predict start of mental decline
Scientists at Washington University School of Medicine in St. Louis have helped identify many of the biomarkers for Alzheimer’s disease that could potentially predict which patients will develop the disorder later in life. Now, studying spinal fluid samples and health data from 201 research participants at the Charles F. and Joanne Knight Alzheimer’s Disease Research Center, the researchers have shown the markers are accurate predictors of Alzheimer’s years before symptoms develop.
“We wanted to see if one marker was better than the other in predicting which of our participants would get cognitive impairment and when they would get it,” said Catherine Roe, PhD, research assistant professor of neurology. “We found no differences in the accuracy of the biomarkers.”
The study, supported in part by the National Institute on Aging, appears in Neurology.
The researchers evaluated markers such as the buildup of amyloid plaques in the brain, newly visible thanks to an imaging agent developed in the last decade; levels of various proteins in the cerebrospinal fluid, such as the amyloid fragments that are the principal ingredient of brain plaques; and the ratios of one protein to another in the cerebrospinal fluid, such as different forms of the brain cell structural protein tau.
The markers were studied in volunteers whose ages ranged from 45 to 88. On average, the data available on study participants spanned four years, with the longest recorded over 7.5 years.
The researchers found that all of the markers were equally good at identifying subjects who were likely to develop cognitive problems and at predicting how soon they would become noticeably impaired.
Next, the scientists paired the biomarkers data with demographic information, testing to see if sex, age, race, education and other factors could improve their predictions.
“Sex, age and race all helped to predict who would develop cognitive impairment,” Roe said. “Older participants, men and African Americans were more likely to become cognitively impaired than those who were younger, female and Caucasian.”
Roe described the findings as providing more evidence that scientists can detect Alzheimer’s disease years before memory loss and cognitive decline become apparent.
“We can better predict future cognitive impairment when we combine biomarkers with patient characteristics,” she said. “Knowing how accurate biomarkers are is important if we are going to some day be able to treat Alzheimer’s before symptoms and slow or prevent the disease.”
Clinical trials are already underway at Washington University and elsewhere to determine if treatments prior to symptoms can prevent or delay inherited forms of Alzheimer’s disease. Reliable biomarkers for Alzheimer’s should one day make it possible to test the most successful treatments in the much more common sporadic forms of Alzheimer’s.
(Source: news.wustl.edu)
In a first-of-its-kind effort to illuminate the biochemical impact of trauma, researchers at NYU Langone Medical Center have discovered a connection between the quantity of cannabinoid receptors in the human brain, known as CB1 receptors, and post-traumatic stress disorder, the chronic, disabling condition that can plague trauma victims with flashbacks, nightmares and emotional instability. Their findings, which appear online today in the journal Molecular Psychiatry, will also be presented this week at the annual meeting of the Society of Biological Psychiatry in San Francisco.
CB1 receptors are part of the endocannabinoid system, a diffuse network of chemicals and signaling pathways in the body that plays a role in memory formation, appetite, pain tolerance and mood. Animal studies have shown that psychoactive chemicals such as cannabis, along with certain neurotransmitters produced naturally in the body, can impair memory and reduce anxiety when they activate CB1 receptors in the brain. Lead author Alexander Neumeister, MD, director of the molecular imaging program in the Departments of Psychiatry and Radiology at NYU School of Medicine, and colleagues are the first to demonstrate through brain imaging that people with PTSD have markedly lower concentrations of at least one of these neurotransmitters —an endocannabinoid known as anandamide—than people without PTSD. Their study, which was supported by three grants from the National Institutes of Health, illuminates an important biological fingerprint of PTSD that could help improve the accuracy of PTSD diagnoses, and points the way to medications designed specifically to treat trauma.
“There’s not a single pharmacological treatment out there that has been developed specifically for PTSD,” says Dr. Neumeister. “That’s a problem. There’s a consensus among clinicians that existing pharmaceutical treatments such as antidepressant simple do not work. In fact, we know very well that people with PTSD who use marijuana—a potent cannabinoid—often experience more relief from their symptoms than they do from antidepressants and other psychiatric medications. Clearly, there’s a very urgent need to develop novel evidence-based treatments for PTSD.”
The study divided 60 participants into three groups: participants with PTSD; participants with a history of trauma but no PTSD; and participants with no history of trauma or PTSD. Participants in all three groups received a harmless radioactive tracer that illuminates CB1 receptors when exposed to positron emissions tomography (PET scans). Results showed that participants with PTSD, especially women, had more CB1 receptors in brain regions associated with fear and anxiety than volunteers without PTSD. The PTSD group also had lower levels of the neurotransmitter anandamide, an endocannabinoid that binds to CB1. If anandamide levels are too low, Dr. Neumeister explains, the brain compensates by increasing the number of CB1 receptors. “This helps the brain utilize the remaining endocannabinoids,” he says.
Much is still unknown about the effects of anandamide in humans but in rats the chemical has been shown to impair memory. “What is PTSD? It’s an illness where people cannot forget what they have experienced,” Dr. Neumeister says. “Our findings offer a possible biological explanation for this phenomenon.”
Current diagnostics for PTSD rely on subjective measures and patient recall, making it difficult to accurately diagnose the condition or discern its symptoms from those of depression and anxiety. Biological markers of PTSD, such as tests for CB1 receptors and anandamide levels, could dramatically improve diagnosis and treatment for trauma victims.
Among the 1.7 million men and women who have served in the wars in Iraq and Afghanistan, an estimated 20% have PTSD. But PTSD is not limited to soldiers. Trauma from sexual abuse, domestic violence, car accidents, natural disaster, violent assault or even a life-threatening medical diagnosis can lead to PTSD. The condition affects nearly 8 million Americans annually.
These findings were made possible through the collaborative efforts of researchers at NYU School of Medicine, Yale School of Medicine, Harvard Medical School, the Department of Veterans Affairs National Center for PTSD and the University of California at Irvine.
(Image caption: Hypothetical cannabinoid receptor CB1 binding to anandamide)
Grammar errors? The brain detects them even when you are unaware
Your brain often works on autopilot when it comes to grammar. That theory has been around for years, but University of Oregon neuroscientists have captured elusive hard evidence that people indeed detect and process grammatical errors with no awareness of doing so.
Participants in the study — native-English speaking people, ages 18-30 — had their brain activity recorded using electroencephalography, from which researchers focused on a signal known as the Event-Related Potential (ERP). This non-invasive technique allows for the capture of changes in brain electrical activity during an event. In this case, events were short sentences presented visually one word at a time.
Subjects were given 280 experimental sentences, including some that were syntactically (grammatically) correct and others containing grammatical errors, such as “We drank Lisa’s brandy by the fire in the lobby,” or “We drank Lisa’s by brandy the fire in the lobby.” A 50 millisecond audio tone was also played at some point in each sentence. A tone appeared before or after a grammatical faux pas was presented. The auditory distraction also appeared in grammatically correct sentences.
This approach, said lead author Laura Batterink, a postdoctoral researcher, provided a signature of whether awareness was at work during processing of the errors. “Participants had to respond to the tone as quickly as they could, indicating if its pitch was low, medium or high,” she said. “The grammatical violations were fully visible to participants, but because they had to complete this extra task, they were often not consciously aware of the violations. They would read the sentence and have to indicate if it was correct or incorrect. If the tone was played immediately before the grammatical violation, they were more likely to say the sentence was correct even it wasn’t.”
When tones appeared after grammatical errors, subjects detected 89 percent of the errors. In cases where subjects correctly declared errors in sentences, the researchers found a P600 effect, an ERP response in which the error is recognized and corrected on the fly to make sense of the sentence.
When the tones appear before the grammatical errors, subjects detected only 51 percent of them. The tone before the event, said co-author Helen J. Neville, who holds the UO’s Robert and Beverly Lewis Endowed Chair in psychology, created a blink in their attention. The key to conscious awareness, she said, is based on whether or not a person can declare an error, and the tones disrupted participants’ ability to declare the errors. But, even when the participants did not notice these errors, their brains responded to them, generating an early negative ERP response. These undetected errors also delayed participants’ reaction times to the tones.
"Even when you don’t pick up on a syntactic error your brain is still picking up on it," Batterink said. "There is a brain mechanism recognizing it and reacting to it, processing it unconsciously so you understand it properly."
The study was published in the May 8 issue of the Journal of Neuroscience.
The brain processes syntactic information implicitly, in the absence of awareness, the authors concluded. “While other aspects of language, such as semantics and phonology, can also be processed implicitly, the present data represent the first direct evidence that implicit mechanisms also play a role in the processing of syntax, the core computational component of language.”
It may be time to reconsider some teaching strategies, especially how adults are taught a second language, said Neville, a member of the UO’s Institute of Neuroscience and director of the UO’s Brain Development Lab.
Children, she noted, often pick up grammar rules implicitly through routine daily interactions with parents or peers, simply hearing and processing new words and their usage before any formal instruction. She likened such learning to “Jabberwocky,” the nonsense poem introduced by writer Lewis Carroll in 1871 in “Through the Looking Glass,” where Alice discovers a book in an unrecognizable language that turns out to be written inversely and readable in a mirror.
For a second language, she said, “Teach grammatical rules implicitly, without any semantics at all, like with jabberwocky. Get them to listen to jabberwocky, like a child does.”
The pain sensations of others can be felt by some people, just by witnessing their agony, according to new research.
A Monash University study into the phenomenon known as somatic contagion found almost one in three people could feel pain when they see others experience pain. It identified two groups of people that were prone to this response - those who acquire it following trauma, injury such as amputation or chronic pain, and those with the condition present at birth, known as the congenital variant.
Presenting her findings at the Australian and New Zealand College of Anaesthetists’ annual scientific meeting in Melbourne earlier this week, Dr Melita Giummarra, from the School of Psychology and Psychiatry, said in some cases people suffered severe painful sensations in response to another person’s pain.
“My research is now beginning to differentiate between at least these two unique profiles of somatic contagion,” Dr Giummarra said.
“While the congenital variant appears to involve a blurring of the boundary between self and other, with heightened empathy, acquired somatic contagion involves reduced empathic concern for others, but increased personal distress.
“This suggests that the pain triggered corresponds to a focus on their own pain experience rather than that of others.”
Most people experience emotional discomfort when they witness pain in another person and neuroimaging studies have shown that this is linked to activation in the parts of the brain that are also involved in the personal experience of pain.
Dr Giummarra said for some people the pain they ‘absorb’ mirrors the location and site of the pain in another they are witnessing and is generally localised.
“We know that the same regions of the brain are activated for these groups of people as when they experience their own pain. First in emotional regions but then there is also sensory activation. It is a vicarious – it literally triggers their pain, Dr Giummarra said”
Dr Giummarra has developed a new tool to characterise the reactions people have to pain in others that is also sensitive to somatic contagion – the Empathy for Pain Scale.