'Network' analysis of the brain may explain features of autism

'Network' analysis of the brain may explain features of autism

EEGs show structural differences in brain connections

A look at how the brain processes information finds a distinct pattern in children with autism spectrum disorders. Using EEGs to track the brain's electrical cross-talk, researchers from Boston Children's Hospital have found a structural difference in brain connections. Compared with neurotypical children, those with autism have multiple redundant connections between neighboring brain areas at the expense of long-distance links.
     The study, using a "network analysis" like that used to study airlines or electrical grids, may help in understanding some classic behaviors in autism. It was published February 27 in BioMed Central's open access journal BMC Medicine, accompanied by a commentary.
      "We examined brain networks as a whole in terms of their capacity to transfer and process information," says Jurriaan Peters, MD, of the Department of Neurology at Boston Children's Hospital, who is co-first author of the paper with Maxime Taquet, a PhD student in Boston Children's Computational Radiology Laboratory. "What we found may well change the way we look at the brains of autistic children."
     Peters, Taquet and senior authors Simon Warfield, PhD, of the Computational Radiology Laboratory and Mustafa Sahin, MD, PhD, of Neurology, analyzed EEG recordings from two groups of autistic children: 16 children with classic autism, and 14 children whose autism is part of a genetic syndrome known as tuberous sclerosis complex (TSC). They compared these readings with EEGs from two control groups—46 healthy neurotypical children and 29 children with TSC but not autism.
In both groups with autism, there were more short-range connections within different brain region, but fewer connections linking far-flung areas.
     A brain network that favors short-range over long-range connections seems to be consistent with autism's classic cognitive profile—a child who excels at specific, focused tasks like memorizing streets, but who cannot integrate information across different brain areas into higher-order concepts.

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Drug Could Make Aging Brains More Youthful?

Declining neural activity can be revved up in older brains, monkey study hints.

National Geographic -- "You can't teach an old brain new tricks—but you can restore its ability to remember the old ones, a new study in monkeys suggests.
Chemicals given to rhesus macaques blocked a brain molecule that slows the firing of the brain's nerve cells, or neurons, as we age—prompting those nerve cells to act young again.
"It's our first glimpse of what's going on physiologically that's causing age-related cognitive decline," said study leader Amy Arnsten, a neurobiologist at Yale University.
"We all assumed, given there's a lot of architectural changes in aged brains ... that we were stuck with it," Arnsten said.
But with the new results, "the hopeful thing is that the neurochemical environment still makes a big difference, and we might be able to remediate some of these things."

Brain's "Sketch Pad" Declines With Age
As the brain gets older, the prefrontal cortex begins to decline quickly.
This part of the brain is responsible for many high-order functions, including maintaining working memories—the ability to keep things on a "mental sketch pad" in the absence of stimuli from an action-based task.
The researchers had previously found that in young brains, nerve cells in the prefrontal cortex excite each other to keep working memories on the brain's slate.
"Those connections depend on the neurochemical environment, [which] has to be just right, like Goldilocks," she said.
But when people get into their 40s and 50s, that part of the brain begins to accumulate too much of a signaling molecule called cAMP, which can stop the cells from firing as efficiently—leading to forgetfulness and distractedness.
The number of seniors in the United States will likely double by 2050, and many of them will struggle to cope with the frenetic information age, according to the study."
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For Hearing Parts of Brain, Deafness Reorganizes Sensory Inputs, Not Behavioral Function

ScienceDaily (May 10, 2011) — "The part of the brain that uses hearing to determine sound location is reorganized in deaf animals to locate visual targets, according to a new study by a team of researchers from Virginia Commonwealth University and the University of Western Ontario in Canada.These findings propose a new theory for cross-modal plasticity: loss of one sensory modality is substituted by another while maintaining the original function of the brain region.
It is known that persons who have suffered major sensory loss, such as deafness, show compensatory, or even superior performance in the remaining senses. This occurs through a process of cross-modal plasticity, where loss of one sensory modality is replaced by the remaining senses. But researchers have not known how the brain region vacated by one sensory modality selects its sensory replacement -- until now.
In a study, published online the week of May 9 in the Early Edition of the Proceedings of the National Academy of Sciences, the team first examined the region of auditory cortex in hearing adult animals that responded to auditory stimuli and controlled orienting and localization behaviors in response to sounds."

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Improved Recovery of Motor Function After Stroke

ScienceDaily (Apr. 19, 2011) — "After the acute treatment window closes, the only effective treatment for stroke is physical/occupational therapy. Now scientists from Children's Hospital Boston report a two-pronged molecular therapy that leads to significant recovery of skilled motor function in a rat model of stroke. Their findings are reported April 20 in the Journal of Neuroscience.
By combining two molecular therapies -- each known to promote some recovery on its own -- the researchers achieved more nerve growth and a greater recovery of motor function than with either treatment alone. One therapy, inosine, is a naturally-present molecule that promotes nerve growth; the other is NEP1-40, an agent that counteracts natural inhibitors of nerve growth.
"When you put these two together, you get much stronger growth of new circuits than either one alone, and very striking functional improvements," says senior author Larry Benowitz, PhD, of the Children's Department of Neurosurgery.
Strokes in humans often damage the motor cortex on one side of the brain, interfering with skilled motor functions on the opposite side of the body. Led by Laila Zai, PhD, a postdoctoral fellow in Benowitz's lab and the study's first author, the researchers modeled this scenario by inducing strokes on one side of the rats' brains -- specifically in a part of the motor cortex that controls forelimb movement. They then examined the rats' ability to perform a skilled reaching task -- retrieving food -- with the forelimb on the opposite side.
After 3 to 4 weeks, rats treated with both inosine and NEP1-40 could perform the task -- which required coordinated movements of the paw and digits -- with success rates equivalent to those before the stroke. Benowitz likens the complexity of this task to a person eating with utensils or operating a joystick."

Tool Predicts Disability Timeline for Progressive Multiple Sclerosis Patients

ScienceDaily (Apr. 13, 2011) — "Many patients with progressive multiple sclerosis (MS) worry how quickly the disease will progress. Now, by noting the presence of certain markers in a commonly performed diagnostic test, Mayo Clinic researchers can predict whether patients will suffer a faster onset of disability and counsel them to help ease anxiety.
The research is being presented at the American Academy of Neurology meeting in Honolulu, Hawaii.
Progressive MS is a disease of the central nervous system that can damage the brain, spinal cord and optic nerves. Over time, this damage can make it difficult or impossible for patients to walk, making them reliant on mobility aids such as walkers or wheelchairs.
"In this study, we found that in patients who developed the progressive form of MS that had preceding relapses, the presence of greater production of one of these molecules, immunoglobulin G, predicted a faster onset of disability," explains Orhun Kantarci, M.D., a Mayo Clinic neurologist and the study's lead author. As physicians better predict the onset of disability, they can better counsel patients by providing answers in a time of uncertainty.
The study looked at cerebrospinal fluid (CSF) test results from a sample of 281 progressive MS patients seen at Mayo Clinic from 2002 to 2007. In general, CSF test results help physicians when the diagnosis is uncertain. For this study, researchers analyzed CSF test results and noticed a relationship between a faster disability rate and abnormally high levels of two proteins -- oligoclonal band and immunoglobulin-G molecule. If patients had the progressive form of MS with proceeding relapses, and their CSF results showed an elevated protein, researchers concluded they will have a faster rate of disability."
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Brain Scans Detect Autism's Signature

ScienceDaily (Dec. 1, 2010) — "An autism study by Yale School of Medicine researchers using functional magnetic resonance imaging (fMRI) has identified a pattern of brain activity that may characterize the genetic vulnerability to developing autism spectrum disorder (ASD). Published Nov. 15 in the early edition of Proceedings of the National Academy of Sciences, the study could eventually lead to earlier and more accurate autism diagnosis.ASD is defined by impaired social interaction and communication, and can disrupt the brain's ability to interpret the movements of other people, known as "biological motion." ASD is a strongly genetic, highly prevalent disorder.
Using fMRI, Yale researchers Martha Kaiser, Kevin Pelphrey and colleagues scanned the brains of children with autism and their unaffected siblings, as well as those of typically developing children as the three groups watched animations of biological movement. The study included 62 children age 4 to 17.
The team identified three distinct "neural signatures": trait markers -- brain regions with reduced activity in children with ASD and their unaffected siblings; state markers -- brain areas with reduced activity found only in children with autism; and compensatory activity -- enhanced activity seen only in unaffected siblings."
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Modulating a Protein in the Brain Could Help Control Alzheimer's Disease

ScienceDaily (Nov. 18, 2010) — A protein known to exist in the brain for more than 30 years, called 5-lipoxygenase, has been found to play a regulatory role in the formation of the amyloid beta in the brain, the major component of plaques implicated in the development of Alzheimer's disease, according to researchers at Temple University's School of Medicine.

The researchers also found that inhibitors of this protein currently used to control asthma could possibly be used to prevent or treat Alzheimer's disease.

The researchers published their findings in the Annals of Neurology.According to Domenico Praticò, an associate professor of pharmacology in Temple's School of Medicine and the study's lead researcher, the 5-Lipoxygenase enzyme is found in abundance mainly in the region of the brain, the hippocampus, involved in memory.

Praticò and his team discovered that 5-lipoxygenase, which unlike most proteins in the brain increases its levels during the aging process. It also controls the activation state of another protein, called gamma secretase, a complex of four elements which are necessary and responsible for the final production of the amyloid beta, a peptide that when produced in excess deposits and forms plaques in the brain. Today the amount of these amyloid plaques in the brain is used as a measurement of the severity of Alzheimer's.

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Controlling Cursors With Thoughts: Faster, Simpler, and More Accurately; Advance Helps People Regulate Their Own Brain Response, With Therapeutic Impl

ScienceDaily (Nov. 16, 2010) — Using a new brain-computer training approach, 14 volunteers learned in only six minutes how to move a screen cursor with their thoughts. Near-instant feedback helped the people quickly master some of their own brain responses.

Researchers have developed a speedier system that allows people to control a cursor with thought alone. Studies show that when people and animals are given feedback about their brain signals, they can gain some control over those signals. It's now possible to acquire that feedback faster than ever before -- in "real time" -- using functional magnetic resonance imaging (fMRI), which registers blood flow in active brain regions.

"For most of us, most of the time, the ongoing activity of the brain is hidden and not under voluntary control," said lead author Anna Rose Childress, PhD, of the University of Pennsylvania School of Medicine. "Brain feedback studies are changing this long-standing, one-way relationship.

"Thought-only cursor control may provide more options for people with "locked-in" syndromes -- in which a person is aware but unable to communicate -- and individuals with brain injuries. Previous trials have also shown that people can learn to control pain using real-time fMRI, and researchers believe this same technique may be applied to other conditions. They theorize that if the structures that underlie these diseases can be controlled, the disease itself can be altered.

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New Technology Allows Medical Workers to Better Assess Brain Injuries

ScienceDaily (Nov. 15, 2010) — A Queen's University neuroscientist is launching a medical tool at the world's largest neuroscience conference in San Diego on Nov. 15. The KINARM Assessment Station will greatly improve the way healthcare workers assess patients suffering from brain injuries and disease.

The new technology, invented by Stephen Scott, is the only objective tool for assessing brain function, and clinical researchers need this tool to develop better therapies for treating brain injury or disease.

KINARM combines a chair with robotic 'arms' and a virtual/augmented reality system that enables neuroscience and rehabilitation researchers to guide their patient through a series of standardized tasks, such as hitting balls with virtual paddles. Once the tests are completed, the system instantly generates a detailed report, pinpointing variations from normal behaviour.

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Gene Associated With Autism May Alter How Brain Functions

WEDNESDAY, Nov. 3 (HealthDay News) -- People with a common genetic variant that's associated with autism have a "disconnect" between their frontal lobe and other areas of the brain important for language, brain scans show.

The disconnect may help explain some of the language and communication difficulties that are characteristic of autism, researchers report in the Nov. 3 issue of Science Translational Medicine.

About one-third of all people carry the variant of the CNTNAP2 gene that is associated with a heightened risk of autism, as well as attention-deficit/hyperactivity disorder, Tourette syndrome, schizophrenia and other language difficulties.

In the study, researchers performed functional MRI brain scans -- which measure blood flow in the brain -- on 32 children who had the gene variant. Half had an autism spectrum disorder, while half were developing normally.Regardless of whether the kids had autism or not, children with the CNTNAP2 "risk" gene showed more activity in the frontal lobe of the brain (specifically, inside the prefrontal cortex) during a "language learning" task than those without the risk gene.

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Brain May Be More Developed at Birth Than Thought

THURSDAY, Nov. 4 (HealthDay News) -- Babies are born with an important collection of fully formed brain networks, including one linked to introspection, a new study shows.

The findings challenge previous ideas about early-stage brain development and activity.Scientists at the MRC Clinical Sciences Center at Imperial College London used functional MRI to examine the brains of 70 babies born at between 29 and 43 weeks. The scans showed that full-term babies have adult-equivalent resting state networks. These are connected systems of neurons that are always active, even when a person is not focusing on a particular task or is asleep.

One fully formed resting state network identified in babies is called the default mode network, which is believed to be involved in introspection and daydreaming. Previous research had indicated this network was incomplete at birth and developed during early childhood.

"Some researchers have said that the default mode network is responsible for introspection -- retrieving autobiographical memories and envisioning the future, etc. The fact that we found it in newborn babies suggests that either being a fetus is a lot more fun than any of us can remember -- lying there happily introspecting and thinking about the future -- or that this theory is mistaken," lead author David Edwards said in a news release from Imperial College London.

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People Blind from Birth Use Visual Brain Area to Improve Other Senses: Can Hear and Feel With Greater Acuity

ScienceDaily (Oct. 10, 2010) — People who have been blind from birth make use of the visual parts of their brain to refine their sensation of sound and touch, according to an international team of researchers led by neuroscientists at Georgetown University Medical Center (GUMC).

Published in the journal Neuron, the scientists say this finding helps explain why the blind have such advanced perception of these senses -- abilities that far exceed people who can see, they say.

Using functional magnetic resonance imaging (fMRI), the researchers found that the blind use specialized "modules" in the visual cortex that process the spatial location of an object when a person localizes it in space. More generally, they believe that the different functional attributes that make up vision, such as analysis of space, patterns, and motion, still exist in the visual cortex of blind individuals. But instead of using those areas to understand what the eyes see, the blind use them to process what they hear and touch because the same components are necessary to process information from those senses.

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Brain Imaging Identifies Differences in Childhood Bipolar Disorder, ADHD

ScienceDaily (Oct. 12, 2010) — Researchers at the University of Illinois at Chicago are the first to use brain imaging to examine the effects of emotion on working memory function in children with pediatric bipolar disorder or attention deficit hyperactivity disorder.

Using functional magnetic resonance imaging, researchers at UIC examined the brain activity of children as they performed a working memory task while viewing faces with different emotions, such as angry, happy or neutral expressions.

The children, ages 10 to 18, were asked to remember the faces and to press a button in the MR-scanner if they saw the same face that was presented two trials earlier. The study involved 23 non-medicated children with bipolar disorder, 14 non-medicated children with ADHD and 19 healthy controls.

"It's a simple yet elegant working memory test that tells us a lot about how their brain remembers stimuli like faces or objects," said Alessandra Passarotti, assistant professor of psychiatry at UIC and lead author of the study. "We also added in an emotional component -- because both disorders show emotional deficits -- to study how their working memory is affected by emotional challenge."

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Human Umbilical Cord Blood Cells Aid Lab Animal Brain Cell Survival After Simulated Stroke

ScienceDaily (Aug. 24, 2010) Human umbilical cord blood cells (HUCB) used to treat cultured rat brain cells (astrocytes) deprived of oxygen appear to protect astrocytes from cell death after stroke-like damage, reports a team of researchers from the University of South Florida (USF) Department of Neurosurgery and Brain Repair.Their study was published in the August, 2010 issue of Stem Cell Review and Reports.

The USF study was carried out with astrocytes cultured in the laboratory (in vitro) and then subjected to oxygen deprivation (hypoxia) and glucose deprivation to model what happens in the human brain during a stroke.

Astrocytes, star-shaped cells in the brain and spinal cord, perform several functions, including support of cells that make up the blood-brain barrier separating circulating blood and spinal fluid.

"When we compared survival of astrocytes grown with and without human umbilical cord blood cells during a period of hypoxia and reduced nutrients, we found that the cord blood cells stabilized the brain cell environment and aided astrocyte survival," said lead author and professor Alison Willing, PhD. "However, the cord blood cells also had an impact on cytokines -- small proteins secreted by cells of the immune system -- and also on glial cells that carry signals between cells."

The researchers discovered that the HUCBs changed cytokine "expression" -- sometimes suppressing inflammation and other times enhancing it.


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How Technology May Improve Treatment for Children With Brain Cancer

ScienceDaily (July 18, 2010) — A study presented at the 52nd Annual Meeting of the American Association of Physicists in Medicine (AAPM) shows that children with brain tumors who undergo radiation therapy (the application of X-rays to kill cancerous cells and shrink tumors) may benefit from a technique known as "intensity modulated arc therapy" or IMAT.

This technique relies upon new features on the latest generation of X-ray therapy equipment that allow X-ray sources to be continuously rotated in any direction around a patient during treatment, potentially increasing the number of directions that the beams come from.

The study, which was conducted by medical physicists at St. Jude Children's Hospital in Memphis, TN, compared different treatment strategies including IMAT for nine children treated with radiation therapy for brain tumors. It showed that IMAT could irradiate these tumors effectively while overall reducing the exposure to the surrounding tissue.

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A Brain-Recording Device That Melts Into Place

ScienceDaily (Apr. 19, 2010) — "Scientists have developed a brain implant that essentially melts into place, snugly fitting to the brain's surface. The technology could pave the way for better devices to monitor and control seizures, and to transmit signals from the brain past damaged parts of the spinal cord.
"These implants have the potential to maximize the contact between electrodes and brain tissue, while minimizing damage to the brain. They could provide a platform for a range of devices with applications in epilepsy, spinal cord injuries and other neurological disorders," said Walter Koroshetz, M.D., deputy director of the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health."

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Seeing a Diagnosis: How an Eye Test Could Aid Alzheimer's Detection

ScienceDaily (Jan. 14, 2010) — A simple and inexpensive eye test could aid detection and diagnosis of major neurological diseases such as Alzheimer's at an earlier stage than is currently possible, according to new research by UCL scientists. The research, led by Professors Francesca Cordeiro & Stephen Moss and published in Cell Death & Disease, demonstrates a new technique that enables retinal, and therefore brain cell death, to be directly measured in real time. The method, demonstrated in an animal model, could not only refine diagnosis of neurodegenerative disorders and help track disease progress; it could also aid the assessment and development of new treatments.

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Strategies to Protect New Brain Cells Against Alzheimer's Disease

ScienceDaily (Dec. 3, 2009) — Stimulating the growth of new neurons to replace those lost in Alzheimer's disease (AD) is an intriguing therapeutic possibility. But will the factors that cause AD allow the new neurons to thrive and function normally? Scientists at the Gladstone Institute of Neurological Disease (GIND) have discovered that two main causes of AD amyloid-beta (Aβ) peptides and apolipoprotein E4 (apoE4) impair the growth of new neurons born in adult brains.

What is more, they have identified drug treatments that can normalize the development of these cells even in the presence of Aβ or apoE4. The findings are described in two separate papers published in the current issue of Cell Stem Cell. Although it had long been assumed that neurons cannot be renewed, it is now well established that new neurons are generated throughout the lives of mammals. One brain region in which new neurons are born in adults, the hippocampus, is involved in learning and memory and affected severely by Alzheimer's disease.

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Love and Envy Linked by Same Hormone, Oxytocin

Studies have shown that the oxytocin hormone has a positive effect on positive feelings. The hormone is released in the body naturally during childbirth and when engaging in sexual relations. (Credit: iStockphoto)

ScienceDaily (Nov. 13, 2009) — A new study carried out at the University of Haifa has found that the hormone oxytocin, the "love hormone," which affects behaviors such as trust, empathy and generosity, also affects opposite behaviors, such as jealousy and gloating. "Subsequent to these findings, we assume that the hormone is an overall trigger for social sentiments: when the person's association is positive, oxytocin bolsters pro-social behaviors; when the association is negative, the hormone increases negative sentiments," explains Simone Shamay-Tsoory who carried out the research.

Previous studies have shown that the oxytocin hormone has a positive effect on positive feelings. The hormone is released in the body naturally during childbirth and when engaging in sexual relations. Participants in an experiment who inhaled the synthetic form of the hormone displayed higher levels of altruistic feelings, and it is supposed that the hormone plays an important role in the formation of relationships between people.

However, in earlier studies carried out by other investigators with rodents, it was found that the hormone is also related to higher levels of aggression. Therefore, it was decided to examine whether the hormone also affects negative social sentiments.

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Stroke Rehabilitation Technology That's Fun And Can Be Used At Home

Using tracking tasks to assess movement problems in the arm after a stroke. (Credit: Image courtesy of University of Southampton)

ScienceDaily (Oct. 10, 2009) — Stroke rehabilitation technology which patients can operate in their own homes while playing computer games, is being developed by academics at the University of Southampton.

Therapists, doctors, engineers and psychologists at the University have come together to set up ARM (Assessment, Rehabilitation, Movement) – a unique initiative that is using ideas from industrial robots to help patients regain and control movement of the arm and hand after a stroke.

"We felt it was important for people to have fun while they recovered," said Professor Jane Burridge of the University of Southampton’s School of Health Sciences. "In fact we find it’s often difficult to get them to stop playing the computer games!"

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