Posts tagged neuroimaging
Articles and news from the latest research reports.
A safer approach for diagnostic medical imaging
Medical imaging is at the forefront of diagnostics today, with imaging techniques like MRI (magnetic resonance imaging), CT (computerized tomography), scanning, and NMR (nuclear magnetic resonance) increasing steeply over the last two decades. However, persisting problems of image resolution and quality still limit these techniques because of the nature of living tissue. A solution is hyperpolarization, which involves injecting the patient with substances that can increase imaging quality by following the distribution and fate of specific molecules in the body but that can be harmful or potentially toxic to the patient. A team of scientists from EPFL, CNRS, ENS and CPE Lyon and ETH Zürich has developed a new generation of hyperpolarization agents that can be used to dramatically enhance the signal intensity of imaged body tissues without presenting any danger to the patient. Their work is published in PNAS.
The team of scientists coordinated by Lyndon Emsley – who is currently Professor at EPFL and ENS Lyon – has developed a new generation of hyperpolarizing agents that are both effective and safe for the patient. The substances, called HYPSOs, were developed by the teams of Christophe Copéret at ETH Zurich and Chloé Thieuleux at CPE-Lyon. The HYPSOs come in the form of a fine, white, porous powder that contains the “tracking” molecules to be hyperpolarized. The HYPSO powder is made up of mesoporous silica (silicon dioxide), which is the major component of sand and is commonly used in nanotechnology.
The silica powder used for the HYPSOs consists of particles, containing pore channels. It has been designed in such a way that the surface of each pore channel can be evenly covered with molecules known as ‘organic radicals’. The radicals are homogeneously distributed, and are able to induce polarization around them. “Controlling the radical distribution was a ‘tour de force’ never achieved in the past, which made the HYPSO materials ideal for this application,” says Christophe Copéret. The pore channels are then filled with a solution of the “tracking” molecules to be hyperpolarized, which act as markers for the imaging – e.g. pyruvate, which is important in the production of energy in cells.
Using novel instruments and methods developed by Sami Jannin at EPFL, the HYPSO sample is hyperpolarized with microwaves in a magnetic field at a very low temperature. The magnetic moments of the atoms are forced to align through a process called “dynamic nuclear polarization”, which transfers the spin energy of the free radicals’ electrons to the markers’ nuclei. The electronic spin magnetism of the hyperpolarizing agent acts on the marker molecule, aligning, or “polarizing”, the nuclei of its atoms.
Hot water is then used to melt and flush the substrate out of the powder. Because of the equipment and conditions needed, the process generally takes place in a room adjacent to the imaging facility. The substrate is then ready to be injected through a long tube into the patient inside the medical imaging device. The entire process only lasts about ten seconds.
Two scans are performed, one with and one without the hyperpolarized agent. When the two images are compared, it is possible to observe the distribution of the hyperpolarized marker in the patient’s body, which, depending on the medical context, can be indicative of disease. For example, accumulation of pyruvate in the prostate could be an early indication of prostate cancer.
The researchers have tested the efficiency of the HYPSOs method on several imaging markers, including pyruvate, acetate, fumarate, pure water, and a simple peptide. Because the HYPSOs is physically retained during dissolution, the technique yields pure solutions of hyperpolarized markers, free of any contaminant. The protocol is therefore simpler and potentially safer for the patient, while its dramatic efficiency on signal quality forecasts the use of this new generation of hyperpolarized agents with a broad range of molecules. As Sami Jannin points out: “We have now received queries of scientists from abroad who are eager to boost their research with this new technology. Amongst other plans, we are very excited about testing these materials in vivo”.
(Source: actu.epfl.ch)
Brain chemical potential new hope in controlling Tourette Syndrome tics
A chemical in the brain plays a vital role in controlling the involuntary movements and vocal tics associated with Tourette Syndrome (TS), a new study has shown.
The research by psychologists at The University of Nottingham, published in the latest edition of the journal Current Biology, could offer a potential new target for the development of more effective treatments to suppress these unwanted symptoms.
The study, led by PhD student Amelia Draper under the supervision of Professor Stephen Jackson, found that higher levels of a neurochemical called GABA in a part of the brain known as the supplementary motor area (SMA) helps to dampen down hyperactivity in the cortical areas that produce movement.
By reducing this hyperactivity, only the strongest signals would get through and produce a movement.
Greater control
Amelia said: “This result is significant because new brain stimulation techniques can be used to increase or decrease GABA in targeted areas of the cortex. It may be possible that such techniques to adjust the levels of GABA in the SMA could help young people with TS gain greater control over their tics.”
Tourette Syndrome is a developmental disorder associated with these involuntary and repetitive vocal and movement tics. Although the exact cause of TS is unknown, research has shown that people with TS have alterations in their brain ‘circuitry’ that are involved in producing and controlling motor functions.
Both the primary motor cortex (M1) and the supplementary motor area (SMA) are thought to be hyperactive in the brains of those with TS, causing the tics which can be both embarrassing and disruptive, especially for children who often find it difficult to concentrate at school.
Tics can be partially controlled by many people with TS but this often takes enormous mental energy and can leave them exhausted towards the end of the day and can often make their tics more frequent and excessive when they ‘relax’. The majority of people diagnosed with TS in childhood manage to gain control over their tics gradually until they have only mild symptoms by early adulthood but this is often too late for some people who have had their education and social friendships disrupted.
Greater detail
The scientists used a technique called magnetic resonance spectroscopy (MRS) in a 7 Tesla Magnetic Resonance Imaging (MRI) scanner to measure the concentration of certain chemicals in the brain known as neurotransmitters which offer an indication of brain activity.
The chemicals were measured in the M1, the SMA and an area involved in visual processing (V1) which was used as a control (comparison) site. They tested a group of young people with TS and a matched group of typical young people with no known disorders.
They discovered that the people with TS had higher concentrations of GABA, which inhibits neuronal activity, in the SMA.
They used other neuroscience techniques to explore the result in greater detail, finding that having more GABA in the SMA meant that the people with Tourette Syndrome had less activity in the SMA when asked to perform a simple motor task, in this case tapping their finger, which they were able to measure using functional MRI.
Using another technique called transcranial magnetic stimulation (TMS) in which a magnetic field is passed over the brain to stimulate neuron activity, they found that those with the most GABA dampen down the brain activity in the M1 when preparing to make a movement. In contrast, the typically developing group increased their activity during movement preparation.
Paradoxical finding
Finally, they considered how GABA was related to brain structure, specifically the white matter fibre bundles that connect the two hemispheres of the brain, a structure called the corpus callosum. They discovered that those with the highest levels of GABA also had the most connecting fibres, leading them to conclude that the more connecting fibres there are then the more excitatory signals are being produced leading to the need for even more GABA to calm this excess hyperactivity.
The results could lead the way to more targeted approaches to controlling tics. New brain techniques such as transcranial direct-current stimulation (tdcs), a form of neurostimulation which uses constant, low level electrical current delivered directly to the brain via electrodes, has already been shown to be successful in increasing or decreasing GABA in targeted areas of the cortex.
Professor Stephen Jackson added: “This finding is paradoxical because prior to our finding, most scientists working on this topic would have thought that GABA levels in TS would be reduced and not increased as we show. This is because a distinction should be made between brain changes that are causes of the disorder (e.g., reduced GABA cells in some key brain areas) and secondary consequences of the disorder (e.g., increased release of GABA in key brain areas) that act to reduce the effects of the disorder.”
New tdcs devices, similar to commercially-available TENS machines, could potentially be produced to be used by young people with TS to ‘train’ their brains to help them gain control over their tics, offering the benefit that they could be relatively cheap and could be used in the home while performing other tasks such as watching television.
(Source: nottingham.ac.uk)
Brain scans reveal ‘grey matter’ differences in media multitaskers
Simultaneously using mobile phones, laptops and other media devices could be changing the structure of our brains, according to new University of Sussex research.
A study published today (24 September) in PLOS ONE reveals that people who frequently use several media devices at the same time have lower grey-matter density in one particular region of the brain compared to those who use just one device occasionally.
The research supports earlier studies showing connections between high media-multitasking activity and poor attention in the face of distractions, along with emotional problems such as depression and anxiety.
But neuroscientists Kep Kee Loh and Dr Ryota Kanai point out that their study reveals a link rather than causality and that a long-term study needs to be carried out to understand whether high concurrent media usage leads to changes in the brain structure, or whether those with less-dense grey matter are more attracted to media multitasking.
The researchers at the University of Sussex’s Sackler Centre for Consciousness Science used functional magnetic resonance imaging (fMRI) to look at the brain structures of 75 adults, who had all answered a questionnaire regarding their use and consumption of media devices, including mobile phones and computers, as well as television and print media.
They found that, independent of individual personality traits, people who used a higher number of media devices concurrently also had smaller grey matter density in the part of the brain known as the anterior cingulate cortex (ACC), the region notably responsible for cognitive and emotional control functions.
Kep Kee Loh says: “Media multitasking is becoming more prevalent in our lives today and there is increasing concern about its impacts on our cognition and social-emotional well-being. Our study was the first to reveal links between media multitasking and brain structure.”
Scientists have previously demonstrated that brain structure can be altered upon prolonged exposure to novel environments and experience. The neural pathways and synapses can change based on our behaviours, environment, emotions, and can happen at the cellular level (in the case of learning and memory) or cortical re-mapping, which is how specific functions of a damaged brain region could be re-mapped to a remaining intact region.
Other studies have shown that training (such as learning to juggle, or taxi drivers learning the map of London) can increase grey-matter densities in certain parts of the brain.
“The exact mechanisms of these changes are still unclear,” says Kep Kee Loh. “Although it is conceivable that individuals with small ACC are more susceptible to multitasking situations due to weaker ability in cognitive control or socio-emotional regulation, it is equally plausible that higher levels of exposure to multitasking situations leads to structural changes in the ACC. A longitudinal study is required to unambiguously determine the direction of causation.”
(Source: sussex.ac.uk)
Brain Wave May Be Used to Detect What People Have Seen, Recognize
Brain activity can be used to tell whether someone recognizes details they encountered in normal, daily life, which may have implications for criminal investigations and use in courtrooms, new research shows.
The findings, published in Psychological Science, a journal of the Association for Psychological Science, suggest that a particular brain wave, known as P300, could serve as a marker that identifies places, objects, or other details that a person has seen and recognizes from everyday life.
Research using EEG recordings of brain activity has shown that the P300 brain wave tends to be large when a person recognizes a meaningful item among a list of nonmeaningful items. Using P300, researchers can give a subject a test called the Concealed Information Test (CIT) to try to determine whether they recognize information that is related to a crime or other event.
Most studies investigating P300 and recognition have been conducted in lab settings that are far removed from the kinds of information a real witness or suspect might be exposed to. This new study marks an important advance, says lead research John B. Meixner of Northwestern University, because it draws on details from activities in participants’ normal, daily lives.
“Much like a real crime, our participants made their own decisions and were exposed to all of the distracting information in the world,” he explains.
“Perhaps the most surprising finding was the extent to which we could detect very trivial details from a subject’s day, such as the color of umbrella that the participant had used,” says Meixner. “This precision is exciting for the future because it indicates that relatively peripheral crime details, such as physical features of the crime scene, might be usable in a real-world CIT — though we still need to do much more work to learn about this.”
To achieve a more realistic CIT, Meixner and co-author J. Peter Rosenfeld outfitted 24 college student participants with small cameras that recorded both video and sound — the students wore the cameras clipped to their clothes for 4 hours as they went about their day.
For half of the students, the researchers used the recordings to identify details specific to each person’s day, which became “probe” items for that person. The researchers also came up with corresponding, “irrelevant” items that the student had not encountered — if the probe item was a specific grocery store, for example, the irrelevant items might include other grocery stores.
For the other half of the students, the “probe” items related to details or items they had not encountered, but which were instead drawn from the recordings of other participants. The researchers wanted to simulate a real investigation, in which a suspect with knowledge of a crime would be shown the same crime-related details as a suspect who may have no crime-related knowledge.
The next day, all of the students returned to the lab and were shown a series of words that described different details or items (i.e., the probe and irrelevant items), while their brain activity was recorded via EEG.
The results showed that the P300 was larger for probe items than for irrelevant items, but only for the students who had actually seen or encountered the probe.
Further analyses revealed that P300 responses effectively distinguished probe items from irrelevant items on the level of each individual participant, suggesting that it is a robust and reliable marker of recognition.
These findings have implications for memory research, but they may also have real-world application in the domain of criminal law given that some countries, like Japan and Israel, use the CIT in criminal investigations.
“One reason that the CIT has not been used in the US is that the test may not meet the criteria to be admissible in a courtroom,” says Meixner. “Our work may help move the P300-based CIT one step closer to admissibility by demonstrating the test’s validity and reliability in a more realistic context.”
Meixner, Rosenfeld, and colleagues plan on investigating additional factors that may impact detection, including whether images from the recordings may be even more effective at eliciting recognition than descriptive words – preliminary data suggest this may be the case.
Scientists track the rise and fall of brain volume throughout life
We can witness our bodies mature, then gradually grow wrinkled and weaker with age, but it is only recently that scientists have been able to track a similar progression in the nerve bundles of our brains. That tissue increases in volume until around age 40, then slowly shrinks. By the end of our lives the tissue is about the volume of a 7-year-old.
So finds a team of Stanford scientists who used a new magnetic resonance imaging technique to show, for the first time, how human brain tissue changes throughout life. Knowing what’s normal at different ages, doctors can now image a patient’s brain, compare it to this standard curve and be able to tell if a person is out of the normal range, much like the way a growth chart can help identify kids who have fallen below their growth curve. The researchers have already used the technique to identify previously overlooked changes in the brain of people with multiple sclerosis.
"This allows us to look at people who have come into the clinic, compare them to the norm and potentially diagnose or monitor abnormalities due to different diseases or changes due to medications," said Jason Yeatman, a graduate student in psychology and first author on a paper published today in Nature Communications. Aviv Mezer, a research associate, was senior author on the paper. Both collaborated with Brian Wandell, a professor of psychology, and his team.
For decades scientists have been able to image the brain using magnetic resonance imaging (MRI) and detect tumors, brain activity or abnormalities in people with some diseases, but those measurements were all subjective. A scientist measuring some aspect of the brain in one lab couldn’t directly compare findings with someone in another lab. And because no two scans could be compared, there was no way to look at a patient’s image and know whether it fell outside the normal range.
Limitation overcome
"A big problem in MRI is variation between instruments," Mezer said. Last year Mezer and Wandell led an interdisciplinary team to develop a technique that can be used to compare MRI scans quantitatively between labs, described in Nature Medicine. “Now with that method we found a way to measure the underlying tissue and not the instrumental bias. So that means that we can measure 100 subjects here and Jason can measure another 100 in Seattle (where he is now a postdoctoral fellow) and we can put them all in a database for the community.”
The technique the team had developed measures the amount of white matter tissue in the brain. That amount of white matter comes primarily from an insulating covering called myelin that allows nerves to fire most efficiently and is a hallmark of brain maturation, though the white matter can also be composed of other types of cells in the brain.
White matter plays a critical role in brain development and decline, and several diseases including schizophrenia and autism are associated with white matter abnormalities. Despite its importance in normal development and disease, no metric existed for determining whether any person’s white matter fell within a normal range, particularly if the people were imaged on different machines.
Mezer and Yeatman decided to use the newly developed quantitative technique to develop a normal curve for white matter levels throughout life. They imaged 24 regions within the brains of 102 people ages 7 to 85, and from that established a set of curves showing the increase and then eventual decrease in white matter in each of the 24 regions throughout life.
What they found is that the normal curve for brain composition is rainbow-shaped. It starts and ends with roughly the same amount of white matter and peaks between ages 30 and 50. But each of the 24 regions changes a different amount. Some parts of the brain, like those that control movement, are long, flat arcs, staying relatively stable throughout life.
Others, like the areas involved in thinking and learning, are steep arches, maturing dramatically and then falling off quickly. (The group did point out that their samples started at age 7 and a lot of brain development had already occurred.)
Continued collaboration
"Regions of the brain supporting high-level cognitive functions develop longer and have more degradation," Yeatman said. "Understanding how that relates to cognition will be really important and interesting." Yeatman is now a postdoctoral scholar at the University of Washington, and Mezer is now an assistant professor at the Hebrew University of Jerusalem. They plan to continue collaborating with each other and with other members of the Wandell lab, looking at how brain composition correlates with learning and how it could be used to diagnose diseases, learning disabilities or mental health issues.
The group has already shown that they can identify people with multiple sclerosis (MS) as falling outside the normal curve. People with MS develop what are known as lesions – regions in the brain or spinal cord where myelin is missing. In this paper, the team showed that they could identify people with MS as being off the normal curve throughout regions of the brain, including places where there are no visible lesions. This could provide an alternate method of monitoring and diagnosing MS, they say.
Wandell has had a particular interest in studying the changes that happen in the brain as a child learns to read. Until now, if a family brought a child into the clinic with learning disabilities, Wandell and other scientists had no way to diagnose whether the child’s brain was developing normally, or to determine the relationship between learning delays and white matter abnormalities.
"Now that we know what the normal distribution is, when a single person comes in you can ask how their child compares to the normal distribution. That’s where this is headed," said Wandell, who is also the Isaac and Madeline Stein Family professor and a Stanford Bio-X affiliate. Wandell runs the Center for Cognitive and Neurobiological Imaging (CNI), where Mezer and the team developed the MRI technique to quantify white matter, and where the scans for this study were conducted.
The ability to share data among scientists is an issue Wandell has championed at the CNI and has been promoting in his work helping the Stanford Neurosciences Institute plan the computing strategy for their new facility. “Sharing of data and computational methods is critical for scientific progress,” Wandell said. In line with that goal, the new standard curve for white matter is something scientists around the world can use and contribute data to.
Down syndrome helps researchers understand Alzheimer’s disease
The link between a protein typically associated with Alzheimer’s disease and its impact on memory and cognition may not be as clear as once thought, according to a new study from the University of Wisconsin-Madison’s Waisman Center. The findings are revealing more information about the earliest stages of the neurodegenerative disease.
The researchers — including lead study author Sigan Hartley, UW-Madison assistant professor of human development and family studies, and Brad Christian, UW-Madison associate professor of medical physics and psychiatry and director of PET Physics in the Waisman Laboratory for Brain Imaging and Behavior — looked at the role of the brain protein amyloid-β in adults living with Down syndrome, a genetic condition that leaves people more susceptible to developing Alzheimer’s. They published their findings in the September issue of the journal Brain.
"Our hope is to better understand the role of this protein in memory and cognitive function," says Hartley. "With this information we hope to better understand the earliest stages in the development of this disease and gain information to guide prevention and treatment efforts."
However, the findings of their study not only may help scientists better understand the condition as it impacts those living with Down syndrome, but they are also relevant to adults without the genetic syndrome.
"There are many unanswered questions about at what point amyloid-β, together with other brain changes, begins to take a toll on memory and cognition and why certain individuals may be more resistant than others," says Hartley.
The UW-Madison scientists, along with collaborators at the University of Pittsburgh, studied 63 healthy adults with Down syndrome, aged 30 to 53, who did not exhibit clinical signs of Alzheimer’s or other forms of dementia. They found that many adults with Down syndrome had high levels of amyloid-β protein but did not suffer the expected negative consequences of the elevated protein.
Alzheimer’s disease is the sixth leading cause of death in the U.S. People with Down syndrome are born with an extra copy of the 21st chromosome, where the gene that codes for the amyloid-β protein resides.
For the study, which was conducted over the course of two days, researchers used magnetic resonance imaging (MRI) and positron emission tomography (PET) scans to capture images of the participants’ brains. Twenty-two of the 63 participants had elevated levels of amyloid-β but showed no evidence of diminished memory or cognitive function when compared to those without elevated levels of the protein. The researchers controlled for differences in age and intellectual level.
Similarly, when assessed as a continuous measure, amyloid-β levels were not tied to differences in memory or cognitive ability, such as changes in visual and verbal memory, attention and language.
(Source: news.wisc.edu)
In a novel brain-imaging study among trauma victims, researchers at NYU Langone Medical Center have linked an opioid receptor in the brain — associated with emotions — to a narrow cluster of trauma symptoms, including sadness, emotional detachment and listlessness. The study, published online today in the journal JAMA Psychiatry, holds important implications for targeted, personalized treatment of post-traumatic stress disorder, or PTSD, a psychiatric condition affecting more than 8 million Americans that can cause a wide range of debilitating psychiatric symptoms.
“Our study points toward a more personalized treatment approach for people with a specific symptom profile that’s been linked to a particular neurobiological abnormality,” says lead author Alexander Neumeister, MD, director of the molecular imaging program in the Departments of Psychiatry and Radiology at NYU School of Medicine, and Co-Director of NYU Langone’s Steven and Alexandra Cohen Veterans Center for the Study of Post-Traumatic Stress Disorder and Traumatic Brain Injury. “Understanding more about where and how symptoms of PTSD manifest in the brain is a critical part of research efforts to develop more effective medications and treatment modalities.”
The new study confirms a growing body of evidence linking a particular set of symptoms to specific brain circuits and chemicals, and bolsters a shift within the field of psychiatry away from “one-size-fits-all treatments” and toward more individualized medication regimens that target highly specific neurobiological components. “We know from previous clinical trials that antidepressants, for example, do not work well for dysphoria and the numbing symptoms often found in PTSD,” Dr. Neumeister added. “Currently available antidepressants are just not linked specifically enough to the neurobiological basis of these symptoms in PTSD. Going forward, our study will help pave the way toward development of better options.”
“People with cancer have a variety of different treatment options available based on the type of cancer that they have,” adds Dr. Neumeister. “We aim to do the same thing in psychiatry. We’re deconstructing PTSD symptoms, linking them to different brain dysfunction, and then developing treatments that target those symptoms. It’s really a revolutionary step forward that has been supported by the National Institute of Mental Health (NIMH) over the past few years in their Research Domain Criteria Project.”
The study, funded by the National Institute of Mental Health (NIMH), compared the brain scans of healthy volunteers with those of clinically diagnosed trauma victims with PTSD, major depression, and generalized anxiety disorder whose symptoms ranged from emotional detachment to isolation. Participants received a harmless radioactive tracer that binds to and illuminates a class of opioid receptors, known as kappa, when exposed to high-resolution positron emission tomography (PET). Kappa opioid receptors bind a potent natural opioid known as dynorphin, which is released by the body during times of stress to help relieve dysphoria or numbing.
Chronic exposure to stress, such as the case with PTSD, taxes kappa opioid receptors, however, causing the receptors to retract inside cells, leaving dynorphin without a place to dock. As a result, patients can experience dysphoria, characterized by feelings of hopelessness, detachment and emotional unease.
Results showed that fewer available kappa opioid receptors in the brain regions believed to govern emotions were associated with more intense feelings of dysphoria, but not feelings of anxious arousal. The findings confirm previous studies in animals linking the opioid-receptor system expressed in these specific brain regions to symptoms of dysphoria. The study also found an association between lower levels of cortisol, a stress hormone, and unavailable kappa opioid receptors, suggesting a new role for cortisol as a biomarker for certain types of PTSD symptoms.
“This is the first brain-imaging study to explore any psychiatric condition using a protein that binds to the kappa opioid receptor system,” notes Dr. Neumeister, who says the data support clinical trials under way at NYU Langone and other institutions of new medications that target kappa opioid receptors and other brain systems that can be linked to specific symptoms in trauma survivors. Such medications could be widely available for the treatment of PTSD in the future if ongoing clinical trials yield encouraging results.
(Image: Alamy)
Study links physical activity in older adults to brain white-matter integrity
Like everything else in the body, the white-matter fibers that allow communication between brain regions also decline with age. In a new study, researchers found a strong association between the structural integrity of these white-matter tracts and an older person’s level of daily activity – not just the degree to which he or she engaged in moderate or vigorous exercise, but also whether the person was sedentary the rest of the time.
The study, reported in the journal PLOS ONE, tracked physical activity in 88 healthy but “low-fit” participants aged 60 to 78. The participants agreed to wear accelerometers during most of their waking hours over the course of a week, and also submitted to brain imaging.
“To our knowledge, this is the first study of its kind that uses an objective measure of physical activity along with multiple measures of brain structure,” said University of Illinois postdoctoral researcher Agnieszka Burzynska, who conducted the research with U. of I. Beckman Institute director Arthur Kramer and kinesiology and community health professor Edward McAuley.
Most studies ask subjects to describe how much physical activity they get, which is subjective and imprecise, Burzynska said. The accelerometer continuously tracks a person’s movement, “so it’s not what they say they do or what they think they do, but we have measured what they are actually doing,” she said.
The researchers assumed that participants’ activity levels over a week accurately reflected their overall engagement, or lack of engagement, in physical activity.
The study also relied on two types of brain imaging. The first, diffusion tensor imaging, offers insight into the structural integrity of a tissue by revealing how water is diffused in the tissue. The second method looks for age-related changes in white matter, called lesions. Roughly 95 percent of adults aged 65 and older have such lesions, Burzynska said. While they are a normal part of aging, their early onset or rapid accumulation may spell trouble, she said.
The team found that the brains of older adults who regularly engaged in moderate-to-vigorous exercise generally “showed less of the white-matter lesions,” Burzynska said.
The association between physical activity and white-matter structural integrity was region-specific, the researchers reported. Older adults who engaged more often in light physical activity had greater structural integrity in the white-matter tracts of the temporal lobes, which lie behind the ears and play a key role in memory, language, and the processing of visual and auditory information.
In contrast, those who spent more time sitting had lower structural integrity in the white-matter tracts connecting the hippocampus, “a structure crucial for learning and memory,” Burzynska said.
“This relationship between the integrity of tracts connecting the hippocampus and sedentariness is significant even when we control for age, gender and aerobic fitness,” she said. “It suggests that the physiological effect of sitting too much, even if you still exercise at the end of the day for half an hour, will have a detrimental effect on your brain.”
The findings suggest that engaging in physical activity and avoiding a sedentary lifestyle are both important for brain health in older age, Burzynska said.
“We hope that this will encourage people to take better care of their brains by being more active,” she said.
Hypersensitivity to Non-Painful Events May Be Part of Pathology in Fibromyalgia
New research shows that patients with fibromyalgia have hypersensitivity to non-painful events based on images of the patients’ brains, which show reduced activation in primary sensory regions and increased activation in sensory integration areas. Findings published in Arthritis & Rheumatology, a journal of the American College of Rheumatology (ACR), suggest that brain abnormalities in response to non-painful sensory stimulation may cause the increased unpleasantness that patients experience in response to daily visual, auditory and tactile stimulation.
Fibromyalgia is a chronic, musculoskeletal syndrome characterized by widespread pain, affecting roughly two percent of the world population, say experts. According to the ACR, five million people in the U.S. have fibromyalgia, which is more prevalent among women. In previous studies fibromyalgia patients report reduced tolerance to normal sensory (auditory, visual, olfactory, and tactile) stimulation in addition to greater sensitivity to pain.
For the present study, researchers used functional magnetic resonance imaging (fMRI) to assess brain response to sensory stimulation in 35 women with fibromyalgia and 25 healthy, age-matched controls. Patients had an average disease duration of 7 years and a mean age of 47.
According to the study, patients reported increased unpleasantness in response to multisensory stimulation in daily life activities. Furthermore, fMRI displayed reduced activation of both the primary and secondary visual and auditory areas of the brain, and increased activation in sensory integration regions. These brain abnormalities mediated the increased unpleasantness to visual, auditory and tactile stimulation that patients reported to experience in daily life.
Lead study author, Dr. Marina López-Solà from the Institute of Cognitive Science, University of Colorado Boulder said, “Our study provides new evidence that fibromyalgia patients display altered central processing in response to multisensory stimulation, which are linked to core fibromyalgia symptoms and may be part of the disease pathology. The finding of reduced cortical activation in the visual and auditory brain areas that were associated with patient pain complaints may offer novel targets for neurostimulation treatments in fibromyalgia patients.”
(Source: eu.wiley.com)
Neuroscientists decode conscious experiences with Hitchcock film
Western researchers have extended their game-changing brain scanning techniques by showing that a short Alfred Hitchcock movie can be used to detect consciousness in vegetative state patients. The study included a Canadian participant who had been entirely unresponsive for 16 years, but is now known to be aware and able to follow the plot of movies.
Lorina Naci, a postdoctoral fellow from Western’s Brain and Mind Institute, and her Western colleagues, Rhodri Cusack, Mimma Anello and Adrian Owen, reported their findings today in The Proceedings of the National Academy of Sciences of the USA (PNAS), in a study titled, A common neural code for similar conscious experiences in different individuals.
While inside the 3T Magnetic Resonance Imaging (MRI) Scanner at Western’s Centre for Functional and Metabolic Mapping, participants watched a highly engaging short film by Alfred Hitchcock. Movie viewing elicited a common pattern of synchronized brain activity. The long-time unresponsive participant’s brain response during the same movie strongly resembled that of the healthy participants, suggesting not only that he was consciously aware, but also that he understood the movie.
“For the first time, we show that a patient with unknown levels of consciousness can monitor and analyze information from their environment, in the same way as healthy individuals,” said Naci, lead researcher on the new study. “We already know that up to one in five of these patients are misdiagnosed as being unconscious and this new technique may reveal that that number is even higher.”
Owen, the Canada Excellence Research Chair in Cognitive Neuroscience and Imaging, explained, “This approach can detect not only whether a patient is conscious, but also what that patient might be thinking. Thus, it has important practical and ethical implications for the patient’s standard of care and quality of life.”
The researchers hope that this novel method will enable better understanding of behaviorally unresponsive patients, who may be misdiagnosed as lacking consciousness.