Nav: Home

Autism breakthrough

December 17, 2015

In a discovery that could offer valuable new insights into understanding, diagnosing and even treating autism, Harvard scientists for the first time have linked a specific neurotransmitter in the brain with autistic behavior.

Using a visual test that is known to prompt different reactions in autistic and normal brains, a research team led by Caroline Robertson, a Junior Fellow of the Harvard Society of Fellows, was able to show that those differences were associated with a breakdown in the signaling pathway used by GABA, one of the brain's chief inhibitory neurotransmitters. The study is described in a December 17 paper in Current Biology.

"This is the first time, in humans, that a neurotransmitter in the brain has been linked to autistic behavior - full stop," Robertson said. "This theory - that the GABA signaling pathway plays a role in autism - has been shown in animal models, but until now we never had evidence for it actually causing autistic differences in humans."

Though it may not lead directly to autism treatments, Robertson said the finding does offer invaluable insight into the disorder and the role neurotransmitters like GABA may play in it. It also suggests that similar visual tests could be used to screen younger children for autism, allowing parents and clinicians to begin early intervention efforts sooner.

Though long believed to play a role in autism - GABA has been widely studied in animal models - evidence supporting GABA's role in the disorder in humans has been elusive.

"Autism is often described as a disorder in which all the sensory input comes flooding in at once, so the idea that an inhibitory neurotransmitter was important fit with the clinical observations," Robertson said. "In addition, people with autism often have seizures - there is a 20 to 25 percent co-morbidity between autism and epilepsy - and we think seizures are runaway excitation in the brain."

To find that evidence, Robertson and colleagues went searching for an easily replicable test that produced consistently different results in those with and without autism, and found it in what visual neuroscientists call binocular rivalry.

Normally, she said, the brain is presented with two slightly different images - one from each eye - that it averages to create the single image we see everyday. The binocular rivalry test, however, forces each eye is take in very different images, with surprising results.

"The end result is that one image is just suppressed entirely from visual awareness for a short period," Robertson said. "So if I show you a picture of a horse and an apple, the horse will entirely go away and you will just see the apple. Eventually, though, the neurons that are forcing that inhibitory signal get tired, and it will switch until you only see the horse. As that process repeats, the two images will rock back and forth."

In earlier studies, Robertson and colleagues showed that while the same process does occur in the autistic brain, the process of oscillating between images can take significantly longer.

"Where the average person might rock back and forth between the two images every three seconds, an autistic person might take twice as long," she said. "They spend the same amount of time in the steady state - where they see only one image - as the average person, it just takes them longer to switch between them, and the second image is not as deeply suppressed."

Using magnetic resonance spectroscopy, a brain imaging technique that can measure the levels of certain neurotransmitters in the brain, researchers found that while those with autism did show normal levels of excitatory neurotransmitters, GABA was far lower than expected.

"What we think we're seeing is evidence of a deficit in the GABA-ergic signaling pathway," Robertson said. "It's not that there's no GABA in the brain...it's that there's some step along that pathway that's broken."

Fixing that pathway, however, is easier said than done.

"It's very diverse," Robertson said. "There are two forms of GABA receptors, A and B, and the GABA A receptor can take multiple forms. We may be able to use this test to look at the effectiveness of drugs to give us a better idea about which of those receptors isn't working properly, but it's very complex.

"If these findings hold true in children as well as adults...right now we cannot diagnose autism in children who cannot speak, but that's when early intervention would be most effective," she continued. "But before children can talk they can see, so we may be able to use this type of visual task to screen children and see if there's something imbalanced in their brain."

Robertson warned, however, that understanding the signaling pathway for GABA won't be a cure-all for autism.

"I'm excited about this study, but there are many other molecules in the brain, and many of them may be associated with autism in some form," she said. "We were looking at the GABA story, but we're not done screening the autistic brain for other possible pathways that may play a role. But this is one, and we feel good about this one."
-end-


Harvard University

Related Autism Articles:

Genes, ozone, and autism
Exposure to ozone in the environment puts individuals with high levels of genetic variation at an even higher risk for developing autism than would be expected just by adding the two risk factors together, a new analysis shows.
A blood test for autism
An algorithm based on levels of metabolites found in a blood sample can accurately predict whether a child is on the autism spectrum of disorder (ASD), based upon a recent study.
New form of autism found
Autism spectrum disorders (ASD) affect around one percent of the world's population and are characterized by a range of difficulties in social interaction and communication.
Autism Speaks MSSNG study expands understanding of autism's complex genetics
A new study from Autism Speaks' MSSNG program expands understanding of autism's complex causes and may hold clues for the future development of targeted treatments.
Paths to Autism: One or Many?
A new report in Biological Psychiatry reports that brain alterations in infants at risk for autism may be widespread and affect multiple systems, in contrast to the widely held assumption of impairment specifically in social brain networks.
Raising a child with autism
Humans are resilient, even facing the toughest of life's challenges.
Explaining autism
Recognizing a need to better understand the biology that produces Autism Spectrum Disorder (ASD) symptoms, scientists at Duke-NUS Medical School (Duke-NUS) and the National Neuroscience Institute (NNI), Singapore, have teamed up and identified a novel mechanism that potentially links abnormal brain development to the cause of ASDs.
Autism breakthrough
Using a visual test that is known to prompt different reactions in autistic and normal brains, Harvard researchers have shown that those differences were associated with a breakdown in the signaling pathway used by GABA, one of the brain's chief inhibitory neurotransmitters.
New options for treating autism
The release of oxytocin leads to an increase in the production of anandamide, which causes mice to display a preference for interacting socially.
The Autism Science Foundation launches the Autism Sisters Project
The Autism Science Foundation, a not-for-profit organization dedicated to supporting and funding autism research, today announced the launch of the Autism Sisters Project, a new initiative that will give unaffected sisters of individuals with autism the opportunity to take an active role in accelerating research into the 'Female Protective Effect.'

Related Autism Reading:

Uniquely Human: A Different Way of Seeing Autism
by Barry M. Prizant (Author)

Winner of the Autism Society of America’s Dr. Temple Grandin Award for the Outstanding Literary Work in Autism

A groundbreaking book on autism, by one of the world’s leading experts, who portrays autism as a unique way of being human—this is “required reading....Breathtakingly simple and profoundly positive” (Chicago Tribune).

Autism therapy typically focuses on ridding individuals of “autistic” symptoms such as difficulties interacting socially, problems in communicating, sensory challenges, and repetitive behavior patterns. Now Dr. Barry M. Prizant... View Details


The Reason I Jump: The Inner Voice of a Thirteen-Year-Old Boy with Autism
by Naoki Higashida (Author), KA Yoshida (Translator), David Mitchell (Translator)

“One of the most remarkable books I’ve ever read. It’s truly moving, eye-opening, incredibly vivid.”—Jon Stewart, The Daily Show

NAMED ONE OF THE BEST BOOKS OF THE YEAR BY
NPR • The Wall Street Journal • Bloomberg Business • Bookish

FINALIST FOR THE BOOKS FOR A BETTER LIFE FIRST BOOK AWARD • NEW YORK TIMES BESTSELLER

You’ve never read a book like The Reason I Jump. Written by Naoki Higashida, a very smart, very self-aware, and very charming thirteen-year-old boy with autism, it is a... View Details


The Survival Guide for Kids with Autism Spectrum Disorders (And Their Parents)
by Elizabeth Verdick (Author), Elizabeth Reeve M.D. (Author)

This positive, straightforward book offers kids with autism spectrum disorders (ASDs) their own comprehensive resource for both understanding their condition and finding tools to cope with the challenges they face every day. Some children with ASDs are gifted; others struggle academically. Some are more introverted, while others try to be social. Some get "stuck" on things, have limited interests, or experience repeated motor movements like flapping or pacing ("stims"). The Survival Guide for Kids with Autism Spectrum Disorders covers all of these areas, with an emphasis on... View Details


A Parent's Guide to High-Functioning Autism Spectrum Disorder, Second Edition: How to Meet the Challenges and Help Your Child Thrive
by Sally Ozonoff (Author), Geraldine Dawson (Author), James C. McPartland (Author)

Many tens of thousands of parents have found the facts they need about high-functioning autism spectrum disorder (ASD), including Asperger syndrome, in this indispensable guide. Leading experts show how you can work with your child's unique impairments--and harness his or her capabilities. Vivid stories and real-world examples illustrate ways to help kids with ASD relate more comfortably to peers, learn the rules of appropriate behavior, and succeed in school. You'll learn how ASD is diagnosed and what treatments and educational supports really work. Updated with the latest research and... View Details


Autism Breakthrough: The Groundbreaking Method That Has Helped Families All Over the World
by Raun K. Kaufman (Author)

As a boy, Raun Kaufman was diagnosed by multiple experts as severely autistic, with an IQ below 30, and destined to spend his life in an institution. Years later, Raun graduated with a degree in Biomedical Ethics from Brown University and has become a passionate and articulate autism expert and educator with no trace of his former condition.
So what happened?

Thanks to The Son-Rise Program, a revolutionary method created by his parents, Raun experienced a full recovery from autism. (His story was recounted in the best-selling book Son-Rise: The Miracle Continues and in the... View Details


Ten Things Every Child with Autism Wishes You Knew: Updated and Expanded Edition
by Ellen Notbohm (Author), Veronica Zysk (Editor)

A bestseller gets even better!  Every parent, teacher, social worker, therapist, and physician should have this succinct and informative book in their back pocket. Framed with both humor and compassion, the book describes ten characteristics that help illuminate—not define—children with autism.

Ellen’s personal experiences as a parent of children with autism and ADHD, a celebrated autism author, and a contributor to numerous publications, classrooms, conferences, and websites around the world coalesce to create a guide for all who come in contact with a... View Details


Asperger's Children: The Origins of Autism in Nazi Vienna
by Edith Sheffer (Author)

A groundbreaking exploration of the chilling history behind an increasingly common diagnosis.

Hans Asperger, the pioneer of autism and Asperger syndrome in Nazi Vienna, has been celebrated for his compassionate defense of children with disabilities. But in this groundbreaking book, prize-winning historian Edith Sheffer exposes that Asperger was not only involved in the racial policies of Hitler’s Third Reich, he was complicit in the murder of children.

As the Nazi regime slaughtered millions across Europe during World War Two, it sorted people according to... View Details


Eating for Autism: The 10-Step Nutrition Plan to Help Treat Your Child’s Autism, Asperger’s, or ADHD
by Elizabeth Strickland (Author)

What your child eats has a major impact on his brain and body function. Eating for Autism is the first book to explain how an autism, Asperger's, PDD-NOS, or ADHD condition can effectively be treated through diet.

Eating for Autism presents a realistic 10-step plan to change your child's diet, starting with essential foods and supplements and moving to more advanced therapies like the Gluten-Free Casein-Free diet. Parents who have followed Strickland's revolutionary plan have reported great improvements in their child's condition, from his mood, sleeping patterns, learning... View Details


I See Things Differently: A First Look at Autism (A First Look At...Series)
by Pat Thomas (Author)

Psychotherapist and counselor Pat Thomas puts her gentle, yet straightforward approach to work in this new addition to Barron's highly acclaimed A First Look At...Series. This book will help children understand what autism is and how it affects someone who has it. A wonderful catalyst for discussion that will help children to better understand and support autistic classmates or siblings. The story line is simple and easily accessible to younger children, who will learn that exploring the personal feelings around social issues is a first step in dealing with them. Full-color... View Details


Neurotribes: The Legacy of Autism and the Future of Neurodiversity
by Steve Silberman (Author), Oliver Sacks (Foreword)

This New York Times–bestselling book upends conventional thinking about autism and suggests a broader model for acceptance, understanding, and full participation in society for people who think differently.
 
What is autism? A lifelong disability, or a naturally occurring form of cognitive difference akin to certain forms of genius? In truth, it is all of these things and more—and the future of our society depends on our understanding it. Wired reporter Steve Silberman unearths the secret history of autism, long suppressed by the same clinicians who became... View Details

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Inspire To Action
What motivates us to take up a cause, follow a leader, or create change? This hour, TED speakers explore stories of inspirational leadership, and what makes some movements more successful than others. Guests include high school history teacher Diane Wolk-Rogers, writer and behavioral researcher Simon Sinek, 2016 Icelandic presidential candidate Halla Tómasdóttir, professor of leadership Jochen Menges, and writer and activist Naomi Klein.
Now Playing: Science for the People

#474 Appearance Matters
This week we talk about appearance, bodies, and body image. Why does what we look like affect our headspace so much? And how do we even begin to research a topic as personal and subjective as body image? To try and find out, we speak with some of the researchers at the Centre for Appearance Research (CAR) at the University of the West of England in Bristol. Psychology Professor Phillippa Diedrichs walks us through body image research, what we know so far, and how we know what we know. Professor of Appearance and Health Psychology Diana Harcourt talks about visible...