Posts tagged brain activity
Articles and news from the latest research reports.
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.
Fronto-limbic brain activity during sleep is believed to support the consolidation of emotional memories in healthy adults. Attention deficit-hyperactivity disorder (ADHD) is accompanied by emotional deficits coincidently caused by dysfunctional interplay of fronto-limbic circuits. This study aimed to examine the role of sleep in the consolidation of emotional memory in ADHD in the context of healthy development. 16 children with ADHD, 16 healthy children, and 20 healthy adults participated in this study. Participants completed an emotional picture recognition paradigm in sleep and wake control conditions. Each condition had an immediate (baseline) and delayed (target) retrieval session. The emotional memory bias was baseline–corrected, and groups were compared in terms of sleep-dependent memory consolidation (sleep vs. wake). We observed an increased sleep-dependent emotional memory bias in healthy children compared to children with ADHD and healthy adults. Frontal oscillatory EEG activity (slow oscillations, theta) during sleep correlated negatively with emotional memory performance in children with ADHD. When combining data of healthy children and adults, correlation coefficients were positive and differed from those in children with ADHD. Since children displayed a higher frontal EEG activity than adults these data indicate a decline in sleep-related consolidation of emotional memory in healthy development. In addition, it is suggested that deficits in sleep-related selection between emotional and non-emotional memories in ADHD exacerbate emotional problems during daytime as they are often reported in ADHD.
Art appreciation is measureable
Is it your own innate taste or what you have been taught that decides if you like a work of art? Both, according to an Australian-Norwegian research team.
Have you experienced seeing a painting or a play that has left you with no feelings whatsoever, whilst a friend thought it was beautiful and meaningful? Experts have argued for years about the feasibility of researching art appreciation, and what should be taken into consideration.
Neuroscientists believe that biological processes that take place in the brain decide whether one likes a work of art or not. Historians and philosophers say that this is far too narrow a viewpoint. They believe that what you know about the artist’s intentions, when the work was created, and other external factors, also affect how you experience a work of art.
Building bridges
A new model that combines both the historical and the psychological approach has been developed.
- We think that both traditions are just as important, although incomplete. We want to show that they complement each other, says Rolf Reber, Professor of Psychology at the University of Bergen. Together with Nicolas Bullot, Doctor of Philosophy at the Macquarie University in Australia, he has developed a new model to help us understand art appreciation. The results have been published in ‘Behavioral and Brain Sciences’ and are commented on by 27 scientists from different disciplines.
- Neuroscientists often measure brain activity to find out how much a testee likes a work of art, without investigating whether he or she actually understands the work. This is insufficient, as artistic understanding also affects assessment, says Reber.
Eye-opening experience
- We know from earlier research that a painting that is difficult – yet possible – to interpret, is felt to be more meaningful than a painting that one looks at and understands immediately. The painter, Eugène Delacroix, made use of this fact to depict war. Joseph Mallord William Turner did the same in ‘Snow storm’. When you have to struggle to understand, you can have an eye-opening experience, which the brain appreciates, explains Reber.
He hopes that other scientists will use the Australian-Norwegian model.
- By measuring brain activity, interviewing test persons about thoughts and reactions, and charting their artistic knowledge, it’s possible to gain new and exciting insight into what makes people appreciate good works of art. The model can be used for visual art, music, theatre and literature, says Reber.
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.
Brain can be trained in compassion
Until now, little was scientifically known about the human potential to cultivate compassion — the emotional state of caring for people who are suffering in a way that motivates altruistic behavior.
A new study by researchers at the Center for Investigating Healthy Minds at the Waisman Center of the University of Wisconsin-Madison shows that adults can be trained to be more compassionate. The report, recently published online in the journal Psychological Science, is the first to investigate whether training adults in compassion can result in greater altruistic behavior and related changes in neural systems underlying compassion.
"Our fundamental question was, ‘Can compassion be trained and learned in adults? Can we become more caring if we practice that mindset?’" says Helen Weng, a graduate student in clinical psychology and lead author of the paper. "Our evidence points to yes."
In the study, the investigators trained young adults to engage in compassion meditation, an ancient Buddhist technique to increase caring feelings for people who are suffering. In the meditation, participants envisioned a time when someone has suffered and then practiced wishing that his or her suffering was relieved. They repeated phrases to help them focus on compassion such as, “May you be free from suffering. May you have joy and ease.”
Participants practiced with different categories of people, first starting with a loved one, someone whom they easily felt compassion for like a friend or family member. Then, they practiced compassion for themselves and, then, a stranger. Finally, they practiced compassion for someone they actively had conflict with called the “difficult person,” such as a troublesome coworker or roommate.
"It’s kind of like weight training," Weng says. "Using this systematic approach, we found that people can actually build up their compassion ‘muscle’ and respond to others’ suffering with care and a desire to help."
Compassion training was compared to a control group that learned cognitive reappraisal, a technique where people learn to reframe their thoughts to feel less negative. Both groups listened to guided audio instructions over the Internet for 30 minutes per day for two weeks. “We wanted to investigate whether people could begin to change their emotional habits in a relatively short period of time,” says Weng.
The real test of whether compassion could be trained was to see if people would be willing to be more altruistic — even helping people they had never met. The research tested this by asking the participants to play a game in which they were given the opportunity to spend their own money to respond to someone in need (called the “Redistribution Game”). They played the game over the Internet with two anonymous players, the “Dictator” and the “Victim.” They watched as the Dictator shared an unfair amount of money (only $1 out of $10) with the Victim. They then decided how much of their own money to spend (out of $5) in order to equalize the unfair split and redistribute funds from the Dictator to the Victim.
"We found that people trained in compassion were more likely to spend their own money altruistically to help someone who was treated unfairly than those who were trained in cognitive reappraisal," Weng says.
"We wanted to see what changed inside the brains of people who gave more to someone in need. How are they responding to suffering differently now?" asks Weng. The study measured changes in brain responses using functional magnetic resonance imaging (fMRI) before and after training. In the MRI scanner, participants viewed images depicting human suffering, such as a crying child or a burn victim, and generated feelings of compassion towards the people using their practiced skills. The control group was exposed to the same images, and asked to recast them in a more positive light as in reappraisal.
The researchers measured how much brain activity had changed from the beginning to the end of the training, and found that the people who were the most altruistic after compassion training were the ones who showed the most brain changes when viewing human suffering. They found that activity was increased in the inferior parietal cortex, a region involved in empathy and understanding others. Compassion training also increased activity in the dorsolateral prefrontal cortex and the extent to which it communicated with the nucleus accumbens, brain regions involved in emotion regulation and positive emotions.
"People seem to become more sensitive to other people’s suffering, but this is challenging emotionally. They learn to regulate their emotions so that they approach people’s suffering with caring and wanting to help rather than turning away," explains Weng.
Compassion, like physical and academic skills, appears to be something that is not fixed, but rather can be enhanced with training and practice. “The fact that alterations in brain function were observed after just a total of seven hours of training is remarkable,” explains UW-Madison psychology and psychiatry professor Richard J. Davidson, founder and chair of the Center for Investigating Healthy Minds and senior author of the article.
"There are many possible applications of this type of training," Davidson says. "Compassion and kindness training in schools can help children learn to be attuned to their own emotions as well as those of others, which may decrease bullying. Compassion training also may benefit people who have social challenges such as social anxiety or antisocial behavior."
Weng is also excited about how compassion training can help the general population. “We studied the effects of this training with healthy participants, which demonstrated that this can help the average person. I would love for more people to access the training and try it for a week or two — what changes do they see in their own lives?”
Both compassion and reappraisal trainings are available on the Center for Investigating Healthy Minds’ website. “I think we are only scratching the surface of how compassion can transform people’s lives,” says Weng.
(Source: news.wisc.edu)
Scientists develop worm EEG to test the effects of drugs
Scientists from the University of Southampton have developed a device which records the brain activity of worms to help test the effects of drugs.
NeuroChip is a microfluidic electrophysiological device, which can trap the microscopic worm Caenorhadbitis elegans and record the activity of discrete neural circuits in its ‘brain’ - a worm equivalent of the EEG.
C. elegans have been enormously important in providing insight into fundamental signalling processes in the nervous system and this device opens the way for a new analysis. Prior to this development, electrophysiological recordings that resolve the activity of excitatory and inhibitory nerve cells in the nervous system of the worm required a high level of technical expertise - single microscopic (1mm long) worms have to be trapped on the end of a glass tube, a microelectrode, in order to make the recording. The worms are very mobile as well as being small and this can be a challenging procedure.
The microfluidic invention consists of a reservoir through which worms can be fed, one after the other, into a narrow fluid-filled channel. The channel tapers at one end and this captures the worm by the front end. The worm is then in the correct orientation for recording the activity of the nervous system in the anterior of its body. The device incorporates metal electrodes, which are connected to an amplifier to make the recording. The design of the trapping channel has been optimised by PhD student Chunxiao Hu, so that the quality of the worm ‘EEG’ recording is sufficient to resolve the activity of components of the neural circuit in the worm’s nervous system.
This device has been used to detect the effects of drugs and is highly suitable for high throughput screens (which allow researchers to quickly conduct millions of chemical, genetic or pharmacological tests) in neurotoxicology and for generic screening for neuroactive drugs. It has more power to resolve discrete effects on excitatory, inhibitory or modulatory transmission than previously possible with behavioural screens.
Lindy Holden-Dye, Professor of Neuroscience at the University of Southampton and lead author of the paper, says: “We are particularly interested in using this as a sensitive new tool for screening compounds for neurotoxicity. It will allow us to precisely quantify sub-lethal effects on neural network activity. It can also provide an information rich platform by reporting the effects of compounds on a diverse array of neurotransmitter pathways, which are implicated in mammalian toxicology. “
The research, which is published in the latest issue of the journal PLOS One, is a joint project between the University’s Centre for Biological Sciences and the Hybrid Biodevices Group.
Waiting for a sign? Researchers find potential brain ‘switch’ for new behavior
You’re standing near an airport luggage carousel and your bag emerges on the conveyor belt, prompting you to spring into action. How does your brain make the shift from passively waiting to taking action when your bag appears?
A new study from investigators at the University of Michigan and Eli Lilly may reveal the brain’s “switch” for new behavior. They measured levels of a neurotransmitter called acetylcholine, which is involved in attention and memory, while rats monitored a screen for a signal. At the end of each trial, the rat had to indicate if a signal had occurred.
Researchers noticed that if a signal occurred after a long period of monitoring or “non-signal” processing, there was a spike in acetylcholine in the rat’s right prefrontal cortex. No such spike occurred for another signal occurring shortly afterwards.
"In other words, the increase in acetylcholine seemed to activate or ‘switch on’ the response to the signal, and to be unnecessary if that response was already activated," said Cindy Lustig, one of the study’s senior authors and an associate professor in the U-M Department of Psychology.
The researchers repeated the study in humans using functional magnetic resonance imaging (fMRI), which measures brain activity, and also found a short increase in right prefrontal cortex activity for the first signal in a series.
To connect the findings between rats and humans, they measured changes in oxygen levels, similar to the changes that produce the fMRI signal, in the brains of rats performing the task.
They again found a response in the right prefrontal cortex that only occurred for the first signal in a series. A follow-up experiment showed that direct stimulation of brain tissue using drugs that target acetylcholine receptors could likewise produce these changes in brain oxygen.
Together, the studies’ results provide some of the most direct evidence, so far, linking a specific neurotransmitter response to changes in brain activity in humans. The findings could guide the development of better treatments for disorders in which people have difficulty switching out of current behaviors and activating new ones. Repetitive behaviors associated with obsessive-compulsive disorder and autism are the most obvious examples, and related mechanisms may underlie problems with preservative behavior in schizophrenia, dementia and aging.
The findings appear in the current issue of Journal of Neuroscience.
Can Brain Scans Really Tell Us What Makes Something Beautiful?
When art meets neuroscience, strange things happen.
Consider the Museum of Scientifically Accurate Fabric Brain Art in Oregon which features rugs and knitting based on a brain scan motif. Or the neuroscientist at the University of Nevada-Reno who scanned the brain of a portrait artist while he drew a picture of a face.
And then there’s the ongoing war of words between scientists who think it’s possible to use analysis of brain activity to define beauty–or even art–and their critics who argue that it’s absurd to try to make sense of something so interpretive and contextual by tying it to biology and the behavior of neurons.
Beauty and the brain
On one side you have the likes of Semir Zeki, who heads a research center called the Institute of Neuroesthetics at London’s University College. A few years ago he started studying what happens in a person’s brain when they look at a painting or listen to a piece of music they find beautiful. He looked at the flip side, too–what goes on in there when something strikes us as ugly.
What he found is that when his study’s subjects experienced a piece of art or music they described as beautiful, their medial orbito-frontal cortex–the part of the brain just behind the eyes–”lit up” in brain scans. Art they found ugly stimulated their motor cortex instead. Zeki also discovered that whether the beauty came through their ears, in music, or their eyes, in art, the brain’s response was the same–it had increased blood flow to what’s known as its pleasure center. Beauty gave the brains a dopamine reward.
Zeki doesn’t go so far as to suggest that the essence of art can be captured in a brain scan. He insists his research really isn’t about explaining what art is, but rather what our neurons’ response to it can tell us about how brains work. But if, in the process, we learn about common characteristics in things our brains find beautiful, his thinking goes, what harm is there in that?
Beware of brain rules?
Plenty, potentially, responds the critics’ chorus. Writing recently in the journal Nature, Philip Ball makes the point that this line of research ultimately could lead to rule-making about beauty, to “creating criteria of right or wrong, either in the art itself or in individual reactions to it.” It conceivably could devolve to “scientific” formulas for beauty, guidelines for what, in music or art or literature, gets the dopamine flowing.
Adds Ball:
Although it is worth knowing that musical ‘chills’ are neurologically akin to the responses invoked by sex or drugs, an approach that cannot distinguish Bach from barbiturates is surely limited.
Others, such as University of California philosophy professor Alva Noe, suggest that to this point at least, brain science is too limiting in what it can reveal, that it focuses more on beauty as shaped by people’s preferences, as opposed to addressing the big questions, such as “Why does art move us?” and “Why does art matter?”
And he wonders if a science built around analyzing events in an individual’s brain can ever answer them. As he wrote in the New York Times:
…there can be nothing like a settled, once-and-for-all account of what art is, just as there can be no all-purpose account of what happens when people communicate or when they laugh together. Art, even for those who make it and love it, is always a question, a problem for itself. What is art? The question must arise, but it allows no definitive answer.
Fad or fortune?
So what of neuroaesthetics? Is it just another part of the “neuro” wave, where brain scans are being billed as neurological Rosetta Stones that proponents claim can explain or even predict behavior–from who’s likely to commit crimes to why people make financial decisions to who’s going to gain weight in the next six months.
More jaded souls have suggested that neuroaesthetics and its bulky cousin, neurohumanities, are attempts to capture enough scientific sheen to attract research money back to liberal arts. Alissa Quart, writing in The Nation earlier this month, cut to the chase:
Neurohumanities offers a way to tap the popular enthusiasm for science and, in part, gin up more funding for humanities. It may also be a bid to give more authority to disciplines that are more qualitative and thus are construed, in today’s scientized and digitalized world, as less desirable or powerful.
Samir Zeki, of course, believes this is about much more than research grants. He really isn’t sure where neuroaesthetics will lead, but he’s convinced that only by “understanding the neural laws,” as he puts it, can we begin to make sense of morality, religion and yes, art.
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.