Seeing the glass as half full: Taking a new look at cognition and aging 11-12

Image credit : Shyam's Imagination Library

From a cognitive perspective, aging is typically associated with decline. As we age, it may get harder to remember names and dates, and it may take us longer to come up with the right answer to a question.

But the news isn’t all bad when it comes to cognitive aging, according to a set of three articles in the July 2014 issue of Perspectives in Psychological Science.

Plumbing the depths of the available scientific literature, the authors of the three articles show how several factors — including motivation and crystallized knowledge — can play important roles in supporting and maintaining cognitive function in the decades past middle age.

Motivation Matters

Lab data offer evidence of age-related declines in cognitive function, but many older adults appear to function quite well in their everyday lives. Psychological scientist Thomas Hess of North Carolina State University sets forth a motivational framework of “selective engagement” to explain this apparent contradiction.

If the cognitive cost of engaging in difficult tasks increases as we age, older adults may be less motivated to expend limited cognitive resources on difficult tasks or on tasks that are not personally relevant to them. This selectivity, Hess argues, may allow older adults to improve performance on the tasks they do choose to engage in, thereby helping to account for inconsistencies between lab-based and real-world data.

Prior Knowledge Brings Both Costs and Benefits

Episodic memory – memory for the events of our day-to-day lives – seems to decline with age, while memory for general knowledge does not. Researchers Sharda Umanath and Elizabeth Marsh of Duke University review evidence suggesting that older adults use prior knowledge to fill in gaps caused by failures of episodic memory, in ways that can both hurt and help overall cognitive performance. While reliance on prior knowledge can make it difficult to inhibit past information when learning new information, it can also make older adults more resistant to learning new erroneous information.

According to Umanath and Marsh, future research should focus on better understanding this compensatory mechanism and whether it can be harnessed in developing cognitive interventions and tools.

Older Adults Aren’t Necessarily Besieged By Fraud

Popular writers and academics alike often argue that older adults, due to certain cognitive differences, are especially susceptible to consumer fraud. Psychological scientists Michael Ross, Igor Grossmann, and Emily Schryer of the University of Waterloo in Canada review the available data to examine whether incidences of consumer fraud are actually higher among older adults. While there isn’t much research that directly answers this question, the research that does exist suggests that older adults may be less frequent victims than other age groups.

Ross, Grossmann, and Schryer find no evidence that older adults are actually more vulnerable to fraud, and they argue that anti-fraud policies should be aimed at protecting consumers of all ages.

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All you need to know about agitated depression 01-2018

Depression is a persistent state of feeling hopeless, sad, or helpless. While there are some common symptoms associated with depression, people can experience depression differently.

One such example is agitated depression. Medical experts may also describe agitated depression as anxious depression or distraught depression.

Though agitated depression is not a distinct type of depression, psychiatric professionals recognize that some people have symptoms of depression as well as agitation.

Fast facts on agitated depression:

Psychiatrists do not define agitated depression as a distinct type of depression.

Agitation can be a common symptom of mood disorders.

Doctors call depression with agitation a "mixed episode" of depression.

Symptoms

Depression with agitation, is known as a "mixed episode" of depression.

Mental health professionals use a manual called the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to diagnose mental health disorders, including depression.

By using the same criteria, doctors across America can diagnose depressive symptoms in the same way.

For a doctor to diagnose someone with depression, the person must have experienced depressed mood or a loss of interest or pleasure in life (anhedonia) for at least 2 weeks.

Also, a person will also have experienced at least five of the following symptoms:

Feelings of sadness, hopelessness, or irritability on a nearly daily basis.

Lack of interest or pleasure in activities almost every day.

Experiencing significant weight loss or appetite loss that results in weight loss.
Difficulty sleeping or sleeping excessively.

Experiencing psychomotor agitation, restlessness, or feelings of being "slowed down."

Feeling fatigued or having a lack of energy nearly every day.

Feeling worthless or having excessive and unexplained guilt almost every day.

Difficulty thinking clearly, concentrating, or making decisions on a daily basis.

Experiencing thoughts of death, thinking of harming one's self, or creating a specific plan for committing suicide.

Agitation is a symptom that can cause a person to experience feelings of uneasiness and anxiety.

Some of the symptoms associated with agitation include:

angry outbursts

clenching fists

disruptive behavior

excessive talking

feeling as if a person cannot sit still or focus
pacing or shuffling feet

tension

wringing of the hands

violent outbursts

A person who has agitated depression experiences feelings of helplessness that can make them feel out of control.

As a result, they can then feel hopeless, which may lead to depressive thoughts. Agitation can cause a person with depression to act impulsively. This could cause a person to hurt themselves or others and engage in harmful behavior.

Depression has many different methods of treatment including self-help. Learn more about the best depression blogs to manage low mood here.

A person with bipolar disorder may experience fluctuating symptoms of depression and mania (an elevated state of being).

Mania is different from agitation because mania causes a person to feel hyper, "high," or overly energetic. A person may only sleep a couple of hours each night and stay awake for extended periods.
Mania does not feel good or euphoric to every person, but it can to some people.

Causes

Depression may be caused by a significant life event, such as the loss of a family member.
Agitation is often a symptom of an underlying mood disorder and is not a condition of its own. The causes of depression itself can be varied and can occur if:

the brain does not regulate mood appropriately

a person has a family history of depression and is more vulnerable to the condition

a person has experienced significant life events that are especially stressful or sad, such as the loss of a family member or divorce

a person has several chronic medical problems

Several of these factors can contribute to depression. However, doctors do not know why a person may experience agitated depression.

A person's temperament that affects their behavior may increase the likelihood that they will experience agitation related to depression.

How is it diagnosed?

Doctors diagnose agitated depression by asking a person to describe the symptoms they are experiencing.

They may ask questions, such as when the symptoms first began, what makes the symptoms better, or what makes the symptoms worse. Sometimes a person's loved ones may also describe the changes they have observed in a person's personality.

A doctor will use the criteria from the DSM-5 to diagnose a person with major depressive disorder, but agitated depression is not diagnosed using DSM-5 criteria. A doctor will also try to rule out other similar conditions, including bipolar disorder.

How is agitated depression treated?

A psychiatrist or other mental health professional may help to treat agitated depression.

Doctors treat agitated depression with a variety of approaches.

In the first instance, a doctor may prescribe medications called sedatives or benzodiazepines.

Examples may include diazepam (Xanax) or lorazepam (Ativan). These medications work quickly to help a person feel calmer and can temporarily relieve agitation.

Additional steps include:

Medications to relieve depression: Doctors may prescribe a variety of drugs to relieve depression, including anti-depressants. If a person does not respond to these medicines, a doctor may add another drug or prescribe a different medication type entirely. Examples can include anti-anxiety medications or mood stabilizers.

Counseling: Seeing a psychiatrist or other mental health professional can help a person identify thoughts and feelings that can signal the start of agitation or depressive symptoms. Therapy can help a person focus on thoughts and behaviors that can help them feel better when they struggle with agitated depression.

Stress-relieving techniques: Relieving stress and depression through physical activity, meditation, deep breathing, and journaling can all help a person cope with feelings agitated depression.
There is no one single solution to treating agitated depression. A doctor must consider a person's unique symptoms.

They will likely take a variety of approaches, including prescribing medications and recommending therapy.

Sometimes it can take several months or even years for a person to find the right combination of medications, therapy, and stress-relieving techniques that help them live better with their agitated depression.

Takeaway

While there is no cure for agitated depression, there are many treatments that can help a person live a healthier, happier life. Although finding the right combination of treatments can take time, help is available.

If a person experiences suicidal thoughts or thoughts of self-harm, they should seek emergency medical attention. Medical professionals can help identify ways to stabilize the person medically, and reduce the risks of them injuring themselves. 

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Breaking the brain’s garbage disposal: Study shows even a small problem causes big effects 01-27

Breaking the brain’s garbage disposal: Study shows even a small problem causes big effects

You wouldn’t think that two Turkish children, some yeast and a bunch of Hungarian fruit flies could teach scientists much.

But in fact, that unlikely combination has just helped an international team make a key discovery about how the brain’s “garbage disposal” process works — and how little needs to go wrong in order for it to break down.

The findings show just how important a cell-cleanup process called autophagy is to our brains. It also demonstrates how even the tiniest genetic change can have profound effects on such an essential function.

The new understanding could lead to better treatments for people whose brain and nerve cells have troubles “taking out the trash.” Some such drugs already exist, but more could follow.

Following a mystery to its end

In a new paper in the online journal eLife, the team describes their painstaking effort to figure out what was wrong in the Turkish siblings, and to understand what it meant. The children have a rare condition called ataxia that makes it harder for them to walk. They also have intellectual disability and developmental delays.

Ataxia is rare–affecting about one in every 20,000 people–and can cause movement problems in people who develop it in adulthood, or a range of symptoms when it arises in children.
Because researchers from the University of Michigan Medical School had published studies about families with multiple cases of ataxia before, Turkish researchers got in touch with them when the children’s parents brought them in for treatment.

That started a long chain of scientific sleuthing that led to today’s publication. First, the U-M team studied samples of the children’s DNA, and used advanced methods to pinpoint the exact genetic mutation that caused their symptoms.

It turned out to be on one of the genes that scientists know play a key role in autophagy, called ATG5. Cells throughout the body trigger their internal garbage crews by turning on this gene and its partners, and using them to make proteins that help clean up the cell.

The junk that these garbage crews clean up includes botched proteins–ones that have been used up or weren’t made right in the first place.

In fact, many forms of ataxia (and lots of other diseases) are caused by genetic problems that result in brain and nerve cells making such damaged, misfolded proteins. The proteins build up inside cells, killing them and causing neurological problems.

So, scientists and drug developers have tried to ramp up autophagy activity. They hope that by cleaning that cellular junk up faster, they can keep it from causing symptoms.

Tiny change – big effects

The children’s ataxia gene problem turned out to be not such a big deal genetically–it was such a slight mutation that it barely changed the way the cells made the protein. But that tiny change was enough to alter the autophagy process, and keep the children’s brain and nerve cells from working properly.

And that’s where the yeast and Hungarian flies come in. Using them, the researchers could see what the children’s problem gene did–and what that meant for the autophagy process. That’s because the autophagy process is so important that organisms ranging from yeast to humans make almost exactly the same ATG5 protein–it’s what scientists call “highly conserved” across species.

What they saw amazed them. The genetic mutation led cells to change just one link in the chain of amino acids that make up the ATG5 protein. The new amino acid even had the same electrical charge as the usual one. But that one changed link happened to be at the exact spot where ATG5 and its partner, called ATG12, connect to one another.

Since the two crucial autophagy partners couldn’t link together as usual, the children’s cells–and the yeast and flies’ cells–couldn’t clean up their cellular trash nearly as well. Autophagy didn’t shut down completely, but less of it happened. And the fruit flies, like the children, had problems walking.
“This is a window into the autophagy system, and the first time where having less autophagy causes ataxia, developmental delays and intellectual disability,” says Margit Burmeister, Ph.D. the U-M neurogeneticist who led the research and is co-senior author on the new paper. “It’s a subtle change, but it shows how important autophagy is in neurological disorders.”

Burmeister and colleagues from the University of Michigan, St. Jude Children’s Research Hospital, Howard Hughes Medical Institute, Istanbul University and Bogazici University in Istanbul and Eötvös Loránd University in Budapest hope the findings lead to autophagy-related treatments.
Meanwhile, they’re still working to understand how the change in ATG12-ATG5 binding actually changes autophagy. They’re looking at cells made with the mutations from other ataxia patients to see if autophagy is also changed.

They’re also looking for more families with ataxias. Each family could hold clues as important as the Turkish children’s mutation did. In fact, Burmeister was in Turkey late in 2015 to work with colleagues to find more potential cases. Small villages with centuries of marriage among people with some relation to one another, and large families, can prove to be important to science.

The acceleration in genetic sequencing and other testing, made possible in the last decade by advances in technology and scientific methods, means they’ll get closer to answers faster. What once took years can now be done in a single year. Having the expertise concentrated at U-M in genetics, autophagy, fruit fly biology, cell biology and more made the work go even faster, says Burmeister. U-M colleagues Daniel Klionsky, Jun Hee Lee and Jun Z. Li were critical to the new research. So were St. Jude colleagues led by Brenda Schulman who made X-ray images of the mutant ATG5 protein, and Zuhal Yapici and Aslihan Tolun, the colleagues in Istanbul and Gabor Juhasz in Budapest.

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Having a purpose in life may improve health of aging brain 03-31

Having a purpose in life may improve health of aging brain

Having a strong sense that your life has meaning and direction may make you less likely to develop areas of brain damage caused by blockages in blood flow as you age. This research is reported in the American Heart Association’s journal Stroke.

When a blockage interrupts blood flow in a vessel within the brain, a stroke can result or brain tissue can be damaged. This damaged tissue, called infarcts, may contribute to dementia, movement problems, disability, and death as people age.

“Mental health, in particular positive psychological factors such as having a purpose in life, are emerging as very potent determinants of health outcomes,” said Patricia Boyle. Ph.D., study co-author and associate professor of behavioral sciences at the Rush Alzheimer’s Disease Center of Rush University Medical Center in Chicago. “Clinicians need to be aware of patients’ mental state and encourage behaviors that will increase purpose and other positive emotional states.”

Researchers analyzed autopsy results on 453 people, average age 84, who volunteered for the Rush Memory and Aging Project and underwent annual physical and psychological evaluations until they died, at an average age of 90. None of the participants had known dementia when they started the study and all participants had agreed to organ donation at death.

Among the participants, 114 had clinically diagnosed stroke. At autopsy, they found:

• Nearly twice that many had macroscopic infarcts (visible to the naked eye) or microinfarcts (visible with microscope) (47.7 percent).

• Participants who had reported a stronger purpose in life were 44 percent less likely to have macroscopic infarcts. The study did not find a significant relationship between purpose in life and microinfarcts.

• Adjusting for vascular disease risk factors, including blood pressure, physical activity, blood pressure, depression, and diabetes did not change the relationship between purpose in life and infarcts;

• The findings related to purpose in life were most significant in small infarcts in the blood vessels supplying deep brain structures (lacunar infarcts);

• The relationship between purpose in life and infarcts was not influenced by Alzheimer’s disease or clinically diagnosed stroke.

Although people’s scores on measures of purpose in life changed little during the course of the study, researchers believe that it can be improved.

“Purpose in life differs for everyone and it is important to be thoughtful about what motivates you, (such as volunteering, learning new things, or being part of the community) so you can engage in rewarding behaviors,” said Lei Yu, Ph.D., study lead author and assistant professor of neurological sciences at the Rush Alzheimer’s Disease Center.

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Major brain pathway rediscovered after century-old confusion, controversy 11-22

Major brain pathway rediscovered after century-old confusion, controversy

A couple of years ago a scientist looking at dozens of MRI scans of human brains noticed something 
surprising. A large, fiber pathway that seemed to be part of the network of connections that process visual information showed up on the scans, but the researcher couldn’t find it mentioned in any of the modern-day anatomy textbooks he had.

“It was this massive bundle of fibers, visible in every brain I examined,” said Jason Yeatman, a research scientist at the University of Washington’s Institute for Learning & Brain Sciences. “It seemed unlikely that I was the first to have noticed this structure; however, as far as I could tell, it was absent from the literature and from all major neuroanatomy textbooks.”With colleagues at Stanford University, where he was a graduate student at the time, Yeatman started some detective work to figure out the identity of that large, mysterious fiber bundle.

In the paper, to be published Nov. 17 by the Proceedings of the National Academy of Sciences, the team describes the history and controversy of the elusive brain pathway, explains how modern MRI techniques rediscovered it, and gives analytical tools researchers can use to identify the brain structure – now known as the vertical occipital fasciculus.

The “aha moment” in identifying the pathway came while Yeatman and Kevin Weiner, a Stanford postdoctoral researcher, were poring over the yellowed pages of 19th-century brain atlases in the basement of the Stanford Medical Library.

“Kevin found an atlas, written by Carl Wernicke near the turn of the (20th) century, that depicted the vertical occipital fasciculus,” Yeatman said. “The last time that atlas had been checked out was 1912, meaning we were the first to view these images in the last century.”

From there, Yeatman and Weiner, who share lead authorship on the paper, did more library research revealing these possibilities for why the pathway was forgotten:

– A scientific disagreement. In an 1881 neuroanatomy atlas, Wernicke, a well-known anatomist who in 1874 discovered “Wernicke’s area,” which is essential for language, wrote about a fiber pathway in a monkey brain he was examining. He called it “senkrechte Occiptalbündel” (translated as vertical occipital bundle). But its vertical orientation contradicted the belief of one of the most renowned neuroanatomists of the era, Theodor Meynert, who asserted that brain connections could only travel in between the front and the back of the brain, not up and down.

– Haphazard naming methods. The 1880s and 1890s were a fertile time in the neuroanatomy world, but scientists lacked a shared process for naming the brain structures they found. Looking at drawings of the brain from this time period, Yeatman and coauthors saw that the fiber pathway that they were looking for appeared in brain atlases but was called different things, including “Wernicke’s perpendicular fasciculus,” “perpendicular occipital fasciculus of Wernicke,” and “stratum profundum convexitatis.”

“When we started, it was just for our own knowledge and curiosity,” said Weiner, who’s also the director of public information at the Institute for Applied Neuroscience, a nonprofit based in Palo Alto, California.

“But, after a while, we realized that there was an important story to tell that contained a series of missing links that have been buried for so long within this puzzle of historical conversation among many who are considered the founders of the entire neuroscience field.”

The researchers used a type of MRI measure called diffusion-weighted imaging to measure the size of the pathway and see where in the brain it went. Across brain scans taken from 37 subjects, they found that the vertical occipital fasciculus begins in the occipital lobe – the part of the brain’s visual processing system located at the back of the head. From there, the fibers spread out like a sheet, connecting brain regions that are important for seeing objects with other brain regions that coordinate which objects to focus attention upon.

“We believe that signals carried by the VOF play a role in many perceptual processes, from recognizing a friend’s face to rapidly reading a page of text,” said Yeatman, who is now studying brain mechanisms involved in learning to read.

In the paper, the researchers also provide an algorithm that others can use on their own data to find the pathway and measure its properties.

“To support reproducible research, our lab makes a strong effort to share software and data,” said Brian Wandell, senior author of the paper and a psychology professor at Stanford. “We believe this is a powerful way to ensure that our findings can be both checked and used in labs around the world.”

The researchers also hope that the algorithm will enable other researchers to study the pathway, possibly leading to a better understanding of its role in human cognition and in patient populations.

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Link seen between seizures and migraines in the brain 11-01

Link seen between seizures and migraines in the brain

Seizures and migraines have always been considered separate physiological events in the brain, but now a team of engineers and neuroscientists looking at the brain from a physics viewpoint discovered a link between these and related phenomena.

Scientists believed these two brain events were separate phenomena because they outwardly affect people very differently. Seizures are marked by electrical hyperactivity, but migraine auras — based on an underlying process called spreading depression — are marked by a silencing of electrical activity in part of the brain. Also, seizures spread rapidly, while migraines propagate slowly.

“We wanted to make a more realistic model of what underlies migraines, which we were working on controlling,” said Steven J. Schiff, Brush Chair Professor of Engineering and director of the Penn State Center for Neural Engineering. “We realized that no one had ever kept proper track of the neuronal energy being used and all of the ions, the charged atoms, going into and out of brain cells.”

Potassium and sodium contribute the ions that control electricity in the brain. The Penn State researchers added fundamental physics principles of conservation of energy, charge and mass to an older theory of this electricity. They kept track of the energy required to run a nerve cell, and kept count of the ions passing into and out of the cells.

The brain needs a constant supply of oxygen to keep everything running because it has to keep pumping the ions back across cell membranes after each electrical spike. The energy supply is directly linked to oxygen concentrations around the cell and the energy required to restore the ions to their proper places is much greater after seizures or migraines.

“We know that some people get both seizures and migraines,” said Schiff. “Certainly, the same brain cells produce these different events and we now have increasing numbers of examples of where single gene mutations can produce the presence of both seizure and migraines in the same patients and families. So, in retrospect, the link was obvious — but we did not understand it.”

The researchers, who also included Yina Wei, recent Penn State Ph.D. in engineering science and mechanics, currently a postdoctoral fellow at University of California-Riverside, and Ghanim Ullah, former Penn State postdoctoral fellow, now a professor of physics at University of South Florida, explored extending older models of brain cell activity with basic conservation principles. They were motivated by previous Penn State experiments that showed the very sensitive link between oxygen concentration with reliable and rapid changes in nerve cell behavior.

What they found was completely unexpected. Adding basic conservation principles to the older models immediately demonstrated that spikes, seizures and spreading depression were all part of a spectrum of nerve cell behavior. It appeared that decades of observations of different phenomena in the brain could share a common underlying link.

“We have found within a single model of the biophysics of neuronal membranes that we can account for a broad range of experimental observations, from spikes to seizures and spreading depression,” the researchers report in a recent issue of the Journal of Neuroscience. “We are particularly struck by the apparent unification possible between the dynamics of seizures and spreading depression.”

While the initial intent was to better model the biophysics of the brain, the connection and unification of seizures and spreading depression was an emergent property of that model, according to Schiff.

“No one, neither us nor our colleagues anticipated such a finding or we would have done this years ago,” said Schiff. “But we immediately recognized what the results were showing and we worked intensively to test the integrity of this result in many ways and we found out how robust it was. Although the mathematics are complex, the linking of these phenomena seems rock solid.”

The ability to better understand the difference between normal and pathological activity within the brain may lead to the ability to predict when a seizure might occur.

“We are not only interested in controlling seizures or migraines after they begin, but we are keen to seek ways to stabilize the brain in normal operating regimes and prevent such phenomena from occurring in the first place,” said Schiff. “This type of unification framework demonstrates that we can now begin to have a much more fundamental understanding of how normal and pathological brain activities relate to each other. We and our colleagues have a lot on our plate to start exploring over the coming years as we build on this finding.”

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Researchers Create AI For DNA Neural Network 10-04

Researchers Create AI For DNA Neural Network

While we’re tempted to drop Terminator references, the shattering awful truth is this new breakthrough leaves us numb. According to a paper released by California Institute of Technology scientists last week, they’ve managed to create artificial intelligence using DNA strands. That’s the oversimplified version of course. Read on for the good stuff.

What they did was build simple neural networks composed of four neurons each that exhibited a capability to employ an input/output network. The hard brainy stuff comes in when the scientists used it for a ‘game.’ According to the source article:

Players dropped DNA strands representing an incomplete set of answers into a test tube. The network then provides the answer–the identity of the correct scientist–by fluorescent signals 

Since the heavy jargon involved with this exciting development is a bit too intimidating, further proof of the awesomeness involved states:

 Caltech said this proof-of-concept technique for pattern recognition shows that the DNA network has the basic ability to think, but it is very slow, taking eight hours to identify the scientists in the game, and the DNA strands can only be used once.

Long story short, artificial intelligence can be achieved at the DNA level. Holy cow, Batman!

Holy cow indeed.

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Ultrasound directed to the human brain can boost sensory performance 01-14

Ultrasound directed to the human brain can boost sensory performance

Whales, bats, and even praying mantises use ultrasound as a sensory guidance system — and now a new study has found that ultrasound can modulate brain activity to heighten sensory perception in humans.

Virginia Tech Carilion Research Institute scientists have demonstrated that ultrasound directed to a specific region of the brain can boost performance in sensory discrimination. The study, published online Jan. 12 in Nature Neuroscience, provides the first demonstration that low-intensity, transcranial-focused ultrasound can modulate human brain activity to enhance perception.

“Ultrasound has great potential for bringing unprecedented resolution to the growing trend of mapping the human brain’s connectivity,” said William “Jamie” Tyler, an assistant professor at the Virginia Tech Carilion Research Institute, who led the study. “So we decided to look at the effects of ultrasound on the region of the brain responsible for processing tactile sensory inputs.”

The scientists delivered focused ultrasound to an area of the cerebral cortex that processes sensory information received from the hand. To stimulate the median nerve — a major nerve that runs down the arm and the only one that passes through the carpal tunnel — they placed a small electrode on the wrist of human volunteers and recorded their brain responses using electroencephalography, or EEG. Then, just before stimulating the nerve, they began delivering ultrasound to the targeted brain region.

The scientists found that the ultrasound both decreased the EEG signal and weakened the brain waves responsible for encoding tactile stimulation.

The scientists then administered two classic neurological tests: the two-point discrimination test, which measures a subject’s ability to distinguish whether two nearby objects touching the skin are truly two distinct points, rather than one; and the frequency discrimination task, a test that measures sensitivity to the frequency of a chain of air puffs.

What the scientists found was unexpected.

The subjects receiving ultrasound showed significant improvements in their ability to distinguish pins at closer distances and to discriminate small frequency differences between successive air puffs.

“Our observations surprised us,” said Tyler. “Even though the brain waves associated with the tactile stimulation had weakened, people actually got better at detecting differences in sensations.”

Why would suppression of brain responses to sensory stimulation heighten perception? Tyler speculates that the ultrasound affected an important neurological balance.

“It seems paradoxical, but we suspect that the particular ultrasound waveform we used in the study alters the balance of synaptic inhibition and excitation between neighboring neurons within the cerebral cortex,” Tyler said. “We believe focused ultrasound changed the balance of ongoing excitation and inhibition processing sensory stimuli in the brain region targeted and that this shift prevented the spatial spread of excitation in response to stimuli resulting in a functional improvement in perception.”

To understand how well they could pinpoint the effect, the research team moved the acoustic beam one centimeter in either direction of the original site of brain stimulation – and the effect disappeared.

“That means we can use ultrasound to target an area of the brain as small as the size of an M&M,” Tyler said. “This finding represents a new way of noninvasively modulating human brain activity with a better spatial resolution than anything currently available.”

Based on the findings of the current study and an earlier one, the researchers concluded that ultrasound has a greater spatial resolution than two other leading noninvasive brain stimulation technologies — transcranial magnetic stimulation, which uses magnets to activate the brain, and transcranial direct current stimulation, which uses weak electrical currents delivered directly to the brain through electrodes placed on the head.

“Gaining a better understanding of how pulsed ultrasound affects the balance of synaptic inhibition and excitation in targeted brain regions — as well as how it influences the activity of local circuits versus long-range connections — will help us make more precise maps of the richly interconnected synaptic circuits in the human brain,” said Wynn Legon, the study’s first author and a postdoctoral scholar at the Virginia Tech Carilion Research Institute. “We hope to continue to extend the capabilities of ultrasound for noninvasively tweaking brain circuits to help us understand how the human brain works.”

“The work by Jamie Tyler and his colleagues is at the forefront of the coming tsunami of developing new safe yet effective noninvasive ways to modulate the flow of information in cellular circuits within the living human brain,” said Michael Friedlander, executive director of the Virginia Tech Carilion Research Institute and a neuroscientist who specializes in brain plasticity. 

“This approach is providing the technology and proof of principle for precise activation of neural circuits for a range of important uses, including potential treatments for neurodegenerative disorders, psychiatric diseases, and behavioral disorders. Moreover, it arms the neuroscientific community with a powerful new tool to explore the function of the healthy human brain, helping us understand cognition, decision-making, and thought.

 This is just the type of breakthrough called for in President Obama’s BRAIN Initiative to enable dramatic new approaches for exploring the functional circuitry of the living human brain and for treating Alzheimer’s disease and other disorders.”

A team of Virginia Tech Carilion Research Institute scientists — including Tomokazu Sato, Alexander Opitz, Aaron Barbour, and Amanda Williams, along with Virginia Tech graduate student Jerel Mueller of Raleigh, N.C. — joined Tyler and Legon in conducting the research.

In addition to his position at the institute, Tyler is an assistant professor of biomedical engineering and sciences at the Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences. In 2012, he shared a Technological Innovation Award from the McKnight Endowment for Neuroscience to work on developing ultrasound as a noninvasive tool for modulating brain activity.

“In neuroscience, it’s easy to disrupt things,” said Tyler. “We can distract you, make you feel numb, trick you with optical illusions. It’s easy to make things worse, but it’s hard to make them better. These findings make us believe we’re on the right path.”

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Brain connectivity study reveals striking differences between men and women 12-05

Brain connectivity study reveals striking differences between men and women

A new brain connectivity study from Penn Medicine published today in theProceedings of National Academy of Sciences found striking differences in the neural wiring of men and women that’s lending credence to some commonly-held beliefs about their behavior.

In one of the largest studies looking at the “connectomes” of the sexes, Ragini Verma, PhD, an associate professor in the department of Radiology at thePerelman School of Medicine at the University of Pennsylvania, and colleagues found greater neural connectivity from front to back and within one hemisphere in males, suggesting their brains are structured to facilitate connectivity between perception and coordinated action. In contrast, in females, the wiring goes between the left and right hemispheres, suggesting that they facilitate communication between the analytical and intuition.

“These maps show us a stark difference–and complementarity–in the architecture of the human brain that helps provide a potential neural basis as to why men excel at certain tasks, and women at others,” said Verma.

For instance, on average, men are more likely better at learning and performing a single task at hand, like cycling or navigating directions, whereas women have superior memory and social cognition skills, making them more equipped for multitasking and creating solutions that work for a group. They have a mentalistic approach, so to speak.

Past studies have shown sex differences in the brain, but the neural wiring connecting regions across the whole brain that have been tied to such cognitive skills has never been fully shown in a large population.

In the study, Verma and colleagues, including co-authors Ruben C. Gur, PhD, a professor of psychology in the department of Psychiatry, and Raquel E. Gur, MD, PhD, professor of Psychiatry, Neurology and Radiology, investigated the gender-specific differences in brain connectivity during the course of development in 949 individuals (521 females and 428 males) aged 8 to 22 years using diffusion tensor imaging (DTI).  DTI is water-based imaging technique that can trace and highlight the fiber  pathways connecting the different regions of the brain, laying the foundation for a structural connectome or network of the whole brain.

This sample of youths was studied as part of the Philadelphia Neurodevelopmental Cohort, a National Institute of Mental Health-funded collaboration between the University of Pennsylvania Brain Behavior Laboratory and the Center for Applied Genomics at the Children’s Hospital of Philadelphia.

The brain is a roadmap of neural pathways linking many networks that help us process information and react accordingly, with behavior controlled by several of these sub-networks working in conjunction.

In the study, the researchers found that females displayed greater connectivity in the supratentorial region, which contains the cerebrum, the largest part of the brain, between the left and right hemispheres. Males, on the other hand, displayed greater connectivity within each hemisphere.

By contrast, the opposite prevailed in the cerebellum, the part of the brain that plays a major role in motor control, where males displayed greater inter-hemispheric connectivity and females displayed greater intra-hemispheric connectivity.

These connections likely give men an efficient system for coordinated action, where the cerebellum and cortex participate in bridging between perceptual experiences in the back of the brain, and action, in the front of the brain, according to the authors. The female connections likely facilitate integration of the analytic and sequential processing modes of the left hemisphere with the spatial, intuitive information processing modes of the right side.

The authors observed only a few gender differences in the connectivity in children younger than 13 years, but the differences were more pronounced in adolescents aged 14 to 17 years and young adults older than 17.

The findings were also consistent with a Penn behavior study, of which this imaging study was a subset of, that demonstrated pronounced sexual differences.  Females outperformed males on attention, word and face memory, and social cognition tests. Males performed better on spatial processing and sensorimotor speed. Those differences were most pronounced in the 12 to 14 age range.

“It’s quite striking how complementary the brains of women and men really are,” said Dr. Ruben Gur.  “Detailed connectome maps of the brain will not only help us better understand the differences between how men and women think, but it will also give us more insight into the roots of neuropsychiatric disorders, which are often sex related.”

Next steps are to quantify how an individual’s neural connections are different from the population; identify which neural connections are gender specific and common in both; and to see if findings from functional magnetic resonance imaging (fMRI) studies fall in line with the connectome data.

Co-authors of the study include Madhura Ingalhalikar, Alex Smith, Drew Parker, Theodore D. Satterthwaite, Mark A. Elliott, Kosha Ruparel, and Hakon Hakonarson of the Section of Biomedical Image Analysis and the Center for Biomedical Image Computing and Analytics.

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Who are you looking at? Why women recognise more faces than men 12-05

Who are you looking at? Why women recognise more faces than men

Numerous studies have reported that women outperform men when it comes to face recognition faces, but most have focused on assessing innate biases in favour of race, gender, and age. Now a major literature review concludes that, in the majority of tests, women are better at face recognition than men, irrespective of all other factors.

In order to test the often-cited theory that women are better at recognising faces than men, psychologists Agneta Herlitz and Johanna Lovén of the Karolinska Institutet, Stockholm, Sweden, have compiled a detailed ‘meta-analysis’ of over 140 existing facial recognition studies. They conclude:

“Our review of the literature … clearly showed that girls and women remembered more faces than boys and men did, irrespective of [the] age of participants. We also found that, in studies using both male and female faces, girls and women remembered more female faces than boys and men did, but not more male faces. However, girls and women outperformed boys and men in [the] recognition of male faces when only male faces were included in the test material.”

The theory that women are better at recognizing, discriminating between, and interpreting facial expressions dates back to the 1970s, and many studies have reported that women outperform men on face-recognition tasks. Women have also been found to outperform men across a number of to-be-remembered materials, such as recall and recognition of words, pictures of objects, and object location. Moreover, there is even evidence that this skill develops in infancy. For example, studies of newly born infants found that girls attended more to a female face than infant boys, whereas boys attended more to a moving object, such as a mobile.

Despite a considerable volume of research on the topic of facial recognition, most studies to date specifically address facial recognition from the perspective of various known biases for race, age, and gender. Herlitz and Lovén therefore set out to test the generalizability of women’s advantage over men in face recognition.

Their literature review, published in the journal Visual Cognition, scoured published data (including advance online publications) up to May 2013 and encompassed papers on the presence and magnitude of:

• the sex difference in face recognition;
• the sex differences in face recognition of male and female faces; and
• the own-gender bias for males and female faces.

In total, more than 140 papers were assessed. These comprised not only ‘conventional’ behavioural studies, but also the physical effects on the brains of test participants by measuring the Blood Oxygen Level-dependent (BOLD) response using functional Magnetic Resonance Imaging (fMRI) scans.

Following a detailed statistical analysis (using the Comprehensive Meta-Analysis technique) of all the research, including the fMRI studies, Herlitz and Lovén found that women’s face recognition advantage is mirrored in the neural correlates of face processing and face recognition.

Why are women and girls more skilled at recognizing faces? And why are they particularly skilled at recognizing their own gender? Herlitz and Lovén hypothesize that the tendency for females to recognize other females may be related to gender labelling and gender-typed imitations (for example, toy preferences at a young age), which results in girls orienting themselves towards other females, which in turn leads to more individuation experience with female faces:

“… [T]there is some evidence suggesting that the female advantage in face recognition and the female own-gender bias develop during the early years, but additional research confirming this hypothesis is needed.”

However, they note that the age at which the female own-gender bias emerges and possibly diminishes has not yet been thoroughly investigated, although one study reported that, for older women, no own-gender bias was observed for either own- or other-age faces. Further studies into the effects of the age of participants and test faces could provide important information about the development and benefits of face recognition.

They also note that, although a large number of studies were reviewed; many more were excluded because they were not specifically focused on gender differences in facial recognition. In addition, further research is needed in order to fully understand the studies that tested recognition of male faces using the Cambridge Face Memory Test (CFMT).

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