neuroscience

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Why Not Scratch That Itch? Study Says Serotonin Is The Reason

(Sarahluv via Compfight)

(Sarahluv via Compfight)

By Nicole Tay
CommonHealth intern

One thing I’ve learned about living in Boston is that the mosquitoes here are vicious. They fly around almost silently, and by the time you notice them, it’s too late; they’ve already made a snack of you.

In one particular case, I was driving home from work and noticed I had an unwelcome passenger. The commute turned into an anxiety-ridden nightmare: lots of swatting while driving and many awkward attempts to lure her out the window. This would not end well, I knew. Sure enough, when I got home, I had bites everywhere. (Apparently, Boston mosquitoes can bite you through tights?!)

The itching comes next. Everyone knows not to scratch bites and itches, but few of us have the superhuman self-discipline to resist the urge. I had even deluded myself into pseudo-scientifically justifying my scratching: “If scratching relieves itchiness, it’s obviously due to some beneficial neuronal pathway, right?”

Wrong. New research from Washington University School of Medicine in St. Louis says otherwise: Scratching can relieve itch by creating minor pain. But when the body responds to pain signals, that response actually can make itching worse.

In essence, when we scratch, the resulting pain interferes with the itchiness and the brain releases serotonin to quell that pain. The serotonin then binds to certain receptors on certain neurons that stimulate the itchy sensation. From the press release:

As part of the study, the researchers bred a strain of mice that lacked the genes to make serotonin. When those genetically engineered mice were injected with a substance that normally makes the skin itch, the mice didn’t scratch as much as their normal littermates. But when the genetically altered mice were injected with serotonin, they scratched as mice would be expected to in response to compounds designed to induce itching.

[To identify the specific serotonin receptor, senior investigator Zhou-Feng] Chen’s team injected mice with a substance that causes itching. They also gave the mice compounds that activated various serotonin receptors on nerve cells. Ultimately, they learned that the receptor known as 5HT1A was the key to activating the itch-specific GRPR neurons in the spinal cord.

To prove they had the correct receptor, Chen’s team also treated mice with a compound that blocked the 5HT1A receptor, and those mice scratched much less. Continue reading

The Bionic Mind: Building Brain Implants To Fight Depression, PTSD

Liss Murphy this summer, with husband Brian, son Owen and sheepdog Ned. (Courtesy)

Liss Murphy, who had surgery to implant Deep Brain Stimulation for depression in 2006 and got much better, on Cape Cod in summer, 2014, with husband Scott, son Owen and sheepdog Ned. (Courtesy)

Ten years ago, with little warning, Liss Murphy fell victim to paralyzing depression, a “complete shutdown.”

She was 31, living in Chicago and working in public relations. The morning of Aug. 13, 2004, she had gone in to the office as usual. “It was Tuesday, and I remember the day so clearly,” she says. “The sun — everything — and I walked out — it was about 11 o’clock — and I never went back. The only time I left the house was to see my psychiatrist, who I saw three times a week.

“I have a hard time believing it was depression, in a way, because it was so pervasive and powerful,” she says. “It invaded every aspect of my life. It took so much away from me. And it happened so fast, and it was so degrading — it took everything from me.”

Murphy came home to Boston, and she tried everything — medications, talk therapy, even repeated rounds of electroshock. But she was barely able to get out of bed for months — then years. Her husband and family and top-flight doctors cared for her, but she sank so low she tried twice to commit suicide.

Finally, a psychiatrist told her about a cutting-edge trial to implant stimulation devices deep in the brains of patients with severe depression. She signed up. In June of 2006, she had the operation.

“My greatest hope that day was to have something go horribly wrong and die on the table,” she says. “I didn’t care.”

She didn’t die. Over the next few months, she got better. These days, eight years after the surgery, if you saw Liss Murphy walking her Old English Sheepdog, Ned, or playing with her 3-year-old son, Owen, only the faint silver scars on her clavicles would hint at anything unusual: That’s where the batteries that power her brain stimulator are implanted.

“We’re taking a wall of computers, basically, and putting it into something that would easily fit inside a box of Tic-Tacs.”
– Jim Moran, Draper Laboratory

But though the surgery changed Murphy’s life, “the trial, on average, didn’t work,” says Dr. Emad Eskandar, the Massachusetts General Hospital neurosurgeon who operated on her. “When you pooled everyone together it didn’t work. But there were like five people out of the 10 we did that had remarkable benefits and went into complete remission. We couldn’t continue with the study because on the average it failed, but for those people in whom it worked, boy did it work.”

Now, as part of a $70-million project funded by the military, researchers are aiming to take brain implants for psychiatric disorders to the next level.

Over the next five years, they aim to build a device that can sit inside a patient’s head, pick up the onset of depression or post-traumatic stress disorder, and head it off before it hits. One implant researcher calls it “a moonshot for the mind.” Continue reading

Beyond Good And Evil: New Science Casts Light On Morality In The Brain

Harvard brain scientist Joshua Buckholtz has never forgotten a convict he met back when he was an undergrad conducting psychological tests in prisons. The man had beaten another man nearly to death for stepping on his foot in a dance club.

“I wanted to ask him,” he recalls, “‘In what world was the reward of beating this person so severely, for this — to me — minor infraction, worth having terrible food and barbed wire around you?’ ”

But over the years, Buckholtz became convinced that this bad deed was a result of faulty brain processing, perhaps in a circuit called the frontostriatal dopamine system. In an impulsive person’s brain, he says, attention just gets so narrowly focused on an immediate reward that, in effect, the future disappears.

He explains: “If you had asked this person, ‘What will happen if you beat someone nearly to death?’, they will tell you, ‘Oh, I’ll be put away.’ It’s not that these people who commit crimes are dumb, but what happens is, in the moment, that information about costs and consequences can’t get in to their decision-making.”

For two decades, researchers have scanned and analyzed the brains of psychopaths and murderers, but they haven’t pinpointed any single source of evil in the brain. What they’ve found instead, as Buckholtz puts it, “is that our folk concepts of good and evil are much more complicated, and multi-faceted, and riven with uncertainty than we ever thought possible before.”

In other words, so much for the old idea that we have an angel on one shoulder and a devil on the other, and that morality is simply a battle between the two. Using new technology, brain researchers are beginning to tease apart the biology that underlies our decisions to behave badly or do good deeds. They’re even experimenting with ways to alter our judgments of what is right and wrong, and our deep gut feelings of moral conviction.

One thing is certain: We may think in simple terms of “good” and “evil,” but that’s not how it looks in the brain at all.

In past years, as neuroscientists and psychologists began to delve into morality, “Many of us were after a moral center of the brain, or a particular system or circuit that was responsible for all of morality,” says assistant professor Liane Young, who runs The Morality Lab at Boston College. But “it turns out that morality can’t be located in any one area, or even set of areas — that it’s all over, that it colors all aspects of our life, and that’s why it takes up so much space in the brain.”

So there’s no “root of all evil.” Rather, says Buckholtz, “When we do brain studies of moral decision-making, what we are led into is an understanding that there are many different paths to antisocial behavior.”

If we wanted to build antisocial offenders, he says, brain science knows some of the recipe: They’d be hyper-responsive to rewards like drugs, sex and status — and the more immediate, the better. “Another thing we would build in is an inability to maintain representations of consequences and costs,” he says. “We would certainly short-circuit their empathic response to other people. We would absolutely limit their ability to regulate their emotions, particularly negative emotions like anger and fear.”

At his Harvard lab, Buckholtz is currently studying the key ability that long-ago convict lacked — to weigh future consequence against immediate gratification. In one ongoing experiment (see the video above), he’s testing whether he can use electrical stimulation to alter people’s choices. Continue reading

In Search Of ‘Computational Psychiatry:’ Why Is It A Hot New Field?

By Suzanne Jacobs
WBUR Intern

It’s around 10 a.m. on a weekday when I walk into a coffee shop that apparently doubles as the preferred study spot of every student on the Boston University campus. My instinct is to leave immediately and find a quieter place to caffeinate, but I’m not here for the coffee. I’m here for information — information on what I’m hearing is one of the hottest new trends in brain science.

Winding my way through tables of frazzled co-eds, I search every face for that “Are you who I’m looking for?” stare, but no one acknowledges me. So I step back out onto the sidewalk and wait. I’m early anyway.

About five minutes later, a young man who would have otherwise been indistinguishable from the crowd of students locks eyes with me from about 20 feet away. “That’s my guy,” I think to myself.

Lights of Ideas (Andrew Ostrovsky)

(Andrew Ostrovsky)

Minutes later, coffees in hand, we’re seated at a small back table, and I put my digital recorder down on it. “Is it okay if I record this?” I ask. He says that’s fine.

At this point, what I really want to do is grab him by the shoulders and yell, “What are you people doing? Let me into your world!” For weeks, I’ve been looking into this new field of research called computational psychiatry, but for the life of me, I can’t figure out what it is. More frustratingly, I can’t figure out why I can’t figure it out, despite a strong science background and hours of reading what little I could find about the topic on the Internet.

But I hold back, press the little red circle on my digital recorder and let the man speak.

In computational psychiatry, “What you try to do is come up with a toy world…,” he begins.

This all started a few weeks earlier when I was perusing the latest edition of Current Opinion in Neurobiology. Don’t ask me why I was perusing Current Opinion in Neurobiology — I don’t know. To avoid doing something else, probably.

One article caught my eye. It was titled “Computational approaches to psychiatry.” A longtime subscriber to the drugs-and-therapy stereotype of psychiatry, I found the idea of new “computational approaches” intriguing, so I read on. Continue reading

‘I’m Not Stupid, Just Dyslexic’ — And How Brain Science Can Help

Sixth-grader Josh Thibeau has been struggling to read for as long as he can remember. He has yet to complete a single Harry Potter book, his personal goal.

Growing up with dyslexia: Josh Thibeau, 12, imagines his brain as an ever-changing maze with turns he must learn to navigate. Here he is with his mother, Janet. (George Hicks/WBUR)

Growing up with dyslexia: Josh Thibeau, 12, thinks of his brain as an ever-changing maze with turns he must learn to navigate. Here he is with his mom, Janet. (George Hicks/WBUR)

When he was in first grade, Josh’s parents enrolled him in a research study at Boston Children’s Hospital investigating the genetics of dyslexia. Since then, Josh has completed regular MRI scans of his brain. Initially, it seemed daunting.

“When we first started, I’m like, ‘Oh no, you’re sending me to like some strange, like, science lab where I’m going to be injected with needles and it’s going to hurt,’ I’m like, ‘I’m never going to see my family again,’ ” says Josh, who lives in West Newbury, Mass.

Josh and his three biological siblings all have dyslexia to varying degrees. Pretty much every day he confronts the reality that his brain works differently than his peers’. He’s even shared scans of his brain with classmates to try to show those differences. Some kids still don’t get it.

“There was a student that said, ‘Are you stupid?’ Because my brain was working in a different way,” Josh says. “And I’m just like, ‘No, I am not stupid…I’m just dyslexic.’ ”

The Pre-Reading Brain 

On average, one or two kids in every U.S. classroom has dyslexia, a brain-based learning disability that often runs in families and makes reading difficult, sometimes painfully so.

Compared to other neurodevelopmental disorders like ADHD or autism, research into dyslexia has advanced further, experts say. That’s partly because dyslexia presents itself around a specific behavior: reading — which, as they say, is fundamental.

Now, new research shows it’s possible to pick up some of the signs of dyslexia in the brain even before kids learn to read. And this earlier identification may start to substantially influence how parents, educators and clinicians tackle the disorder.

Until recently (and sometimes even today) kids who struggled to read were thought to lack motivation or smarts. Now it’s clear that’s not true: Dyslexia stems from physiological differences in the brain circuitry. Those differences can make it harder, and less efficient, for children to process the tiny components of language, called phonemes.

And it’s much more complicated than just flipping your “b’s and “d’s.” To read, children need to learn to map the sounds of spoken language — the “KUH”, the “AH”, the “TUH” — to their corresponding letters. And then they must grasp how those letter symbols, the “C” “A” and “T”, create words with meaning. Kids with dyslexia have far more trouble mastering these steps automatically.

For these children, the path toward reading is often marked by struggle, anxiety and feelings of inadequacy. In general, a diagnosis of dyslexia usually means that a child has experienced multiple failures at school.

But collaborations currently underway between neuroscientists at MIT and Children’s Hospital may mark a fundamental shift in addressing dyslexia, and might someday eliminate the anguish of repeated failure. In preliminary findings, researchers report that brain measures taken in kindergartners — even before the kids can read — can “significantly” improve predictions of how well, or poorly, the children can master reading later on.

Implicated in dyslexia: The arcuate fasciculus is an arch-shaped bundle of fibers that connects the frontal language areas of the brain to the areas in the temporal lobe that are important for language (left). Researchers found that kindergarten children with strong pre-reading scores have a bigger, more robust and well-organized arcuate fasciculus (bottom right) while children with very low scores have a small and not particularly well-organized arcuate fasciculus (top right). (Zeynep Saygin/MIT)

Implicated in dyslexia: The arcuate fasciculus is an arch-shaped bundle of fibers that connects the frontal language areas of the brain to the areas in the temporal lobe that are important for language (left). Researchers found that kindergarten children with strong pre-reading scores have a bigger, more robust and well-organized arcuate fasciculus (bottom right) while children with very low scores have a small and not particularly well-organized arcuate fasciculus (top right). (Zeynep Saygin/MIT)

Pinpointing The White Matter Culprit

Using cutting-edge MRI technology, the researchers are able to pinpoint a specific neural pathway, a white matter tract in the brain’s left hemisphere that appears to be related to dyslexia: It’s called the arcuate fasciculus.

“Maybe the most surprising aspect of the research so far is how clear a signal we see in the brains of children who are likely to go on to be poor readers.”
– MIT neuroscientist John Gabrieli

“It’s an arch-shaped bundle of fibers that connects the frontal language areas of the brain to the areas in the temporal lobe that are important for language,” Elizabeth Norton, a neuroscientist at MIT’s McGovern Institute of Brain Research, explains.

In her lab, Norton shows me brain images from the NIH-funded kindergartner study, called READ (for Researching Early Attributes of Dyslexia).

“We see that in children who in kindergarten already have strong pre-reading scores, their arcuate fasciculus is both bigger and more well organized,” she says. On the other hand: “A child with a score of zero has a very small and not particularly organized arcuate fasciculus.”

She says we’re not quite ready to simply take a picture of your child’s brain and say “Aha, this kid is going to have dyslexia,” but we’re getting closer to that point. Continue reading

Your Brain On Junk Food: ‘Making Us Crazy’ — But Might Fish Help?

By Suzanne E. Jacobs
CommonHealth intern

An urban planner and a biochemist walk into a seafood restaurant.

Okay, that joke’s going nowhere, but last week an urban planner and a biochemist did walk into a classroom at MIT. In a talk titled “Junk Food and the Modern Mind,” the unusual duo explained to a room full of people how seafood’s effects on the human brain could bridge their seemingly disparate fields.

The urban planner was Lynn Todman, a visiting scholar at MIT. Todman has spent the past nine years working to improve mental health and reduce violence among residents of some of Chicago’s roughest neighborhoods.

(Wikimedia Commons)

(Wikimedia Commons)

Last year, Todman held a focus group with adult men in Chicago. At one point, she recalled, one of the men said, “This food is making us crazy,” referring to the unhealthy options common in urban food deserts. Having read up on studies linking nutrition and aggression, Todman took what he said seriously.

“Now, I’ve been doing community based work for a long time, and I know that residents often understand social realities long before we do in the academy, and even though their understanding might be shaped by a series of anecdotes strung together to suggest a trend or pattern, I attribute very real meaning to what residents say about their communities and the observations about the world that they live in,” she said.

Enter Capt. Joe Hibbeln, the biochemist.

Hibbeln, who is also a psychiatrist, works at the National Institutes of Health as a nutritional neuroscientist and is one of the world’s leading experts on the role of fats in brain development.

His claim: a diet rich in omega-3 fatty acids and low in omega-6 fatty acids can make people happier and less aggressive. Continue reading

On Perception (And Pancakes): How The Brain Keeps Vision Stable

By Alexandra Morris
CommonHealth Intern

You probably didn’t think Julia Roberts could teach you much about subtle, yet critical, brain functions.

But, it turns out, she can. Recall Roberts in her iconic film “Pretty Woman.” In one scene, she is eating a croissant. But as the camera pans back to her, the croissant turned into a pancake.

It’s likely that many of us missed that blooper, and now we know why. Scientists have discovered a brain mechanism that smooths our field of vision so that we don’t notice certain subtle visual changes — such as a croissant becoming a pancake in an otherwise identical scene.

In a paper published last month in Nature Neuroscience, researchers from the University of California, Berkeley have identified a brain mechanism that helps to stabilize our field of vision. They call it, a “continuity field” — a process the brain uses to merge similar objects seen within a 15-second timeframe.

“It seems like a very odd thing the brain is doing that could make us less accurate,” said the study’s lead author, Jason Fischer, who is now a postdoctoral fellow in the Department of Brain and Cognitive Sciences at MIT. “But in fact there is this huge benefit to it — and that is stabilizing perception over time.”

To measure this process, researchers showed study participants an image with alternating light and dark bars, or “gratings,” at a random angle every five seconds. The participants were then asked to move a white bar to match the tilt of the grating that had been shown.

Here’s the video:

Researchers found that while the white bars generally aligned with the image, there were subtle differences that were biased toward the previous three or so images. These differences could be attributed to the continuity field.

Imagine, now, for example, you are driving down a highway in the pouring rain and you’re trying to read a road sign. The windshield wipers are moving; the raindrops are hitting your windshield. As you’re looking at the sign, you’re experiencing constant interruptions in your visual stream. In that case, the changes that the continuity field is causing us to miss are the raindrops and windshield wipers — you may even fail to notice them after a while. The continuity field, for the most part, is beneficial — it blocks the stuff we don’t want to see. Continue reading

Why To Exercise Today: It Even Appears To Help Your Eyes

(Wikimedia Commons)

(Wikimedia Commons)

God help us, when will it ever stop? Is there no organ, no medical condition, no tiny part of the human body that is not helped by exercise?

A new mouse study in the The Journal of Neuroscience finds that exercise appears to be good for the retina, and may even slow the development of age-related macular degeneration, which is estimated to affect nearly 2 million older Americans. The key appears to be a helpful protein called brain-derived neurotrophic factor. From the press release:

Moderate aerobic exercise helps to preserve the structure and function of nerve cells in the retina after damage, according to an animal study appearing February 12 in The Journal of Neuroscience. The findings suggest exercise may be able to slow the progression of retinal degenerative diseases.

Age-related macular degeneration, one of the leading causes of blindness in the elderly, is caused by the death of light-sensing nerve cells in the retina called photoreceptors. Although several studies in animals and humans point to the protective effects of exercise in neurodegenerative diseases or injury, less is known about how exercise affects vision.

Machelle Pardue, PhD, together with her colleagues Eric Lawson and Jeffrey H. Boatright, PhD, at the Atlanta VA Center for Visual and Neurocognitive Rehabilitation and Emory University, ran mice on a treadmill for two weeks before and after exposing the animals to bright light that causes retinal degeneration. The researchers found that treadmill training preserved photoreceptors and retinal cell function in the mice.

“This is the first report of simple exercise having a direct effect on retinal health and vision,” Pardue said. “This research may one day lead to tailored exercise regimens or combination therapies in treatments of blinding diseases.” Continue reading

Your Brain On Poverty: Low-Income Childhood Linked To Smaller Brain

Young children living in poverty appear to have smaller brain volumes in critical areas, according to researchers at Washington University School of Medicine. But poverty’s detrimental impact on brain development may be mediated by basic early interventions like compassionate parenting and caregiving, the report says.

(Digital Shotgun/flickr)

(Digital Shotgun/flickr)

Growing up poor is already known to be associated with a higher risk of “poor cognitive outcomes” and school performance, the researchers note. But what’s fairly new here is how outside economic forces play out in the development of a child’s brain. According to the study, published in JAMA Pediatrics Monday:

Poverty was associated with smaller white and cortical gray matter and hippocampal and amygdala volumes. The effects of poverty on hippocampal volume were mediated by caregiving support/hostility on the left and right, as well as stressful life events on the left.

The finding that exposure to poverty in early childhood materially impacts brain development at school age further underscores the importance of attention to the well-established deleterious effects of poverty on child development. Continue reading

The Genetics Of Autism: Inside The Brains Of The Supple Boys

Don’t miss Lynn Jolicoeur’s excellent piece on WBUR this morning about the genetics of autism and the two young Natick boys, Tommy and Stuart Supple, whose gene mutations are the focus of research by Stanford neuroscientist Dr. Thomas Sudhof.

(Jesse Costa/WBUR)

(Jesse Costa/WBUR)

From Lynn’s story:

…The Stanford University neuroscientist — who this year shared the Nobel Prize in medicine for his decades of study into how brain cells communicate — has been studying Tommy and Stuart’s genes, specifically an alteration in one gene, for five years. The Supples hosted Sudhof Wednesday night at a Boston fundraiser in support of his research into the functioning of brain synapses in autism…

According to the Supples, Sudhof’s work is helping conquer the “defeatism” surrounding the neurocognitive disorder.

“He doesn’t think this is unknowable at all. He thinks that it’s very knowable,” Kate Supple said. “We all put so much time and effort into dealing with the symptoms of autism. But you also have to look to deal with the underlying disease.”

For many parents of children with autism, the disorder is a mystery. They have no idea what caused it and focus on therapies to help address the symptoms. But after the blow of both boys being diagnosed before their 2nd birthdays, the Supples sought out private genetic testing without the encouragement of their doctors. Continue reading