Autism spectrum disorder has not yet been linked to a single cause, due to the wide range of symptoms and severity. However, a study by researchers at the University of Virginia suggests a promising new approach to finding answers, one that could lead to advances in the study of other neurological conditions.
Current approaches to autism research involve observing and understanding the disorder through studying its behavioral consequences, using techniques such as functional magnetic resonance imaging that map the brain’s responses to stimuli and activity, but little work has been done to understand what is causing those responses.
However, researchers at UVA’s College and Graduate School of Arts and Sciences have been able to better understand the physiological differences between the brain structures of autistic and non-autistic individuals by using diffusion MRI, a technique that measures the Molecular diffusion in biological tissue. observe how water moves through the brain and interacts with cell membranes. The approach has helped the UVA team develop mathematical models of brain microstructure that have helped identify structural differences in the brains of people with and without autism.
“It hasn’t been well understood what those differences might be,” said Benjamin Newman, a postdoctoral researcher in the UVA Department of Psychology, recent graduate of the UVA School of Medicine’s neuroscience graduate program and lead author of a published paper. this month in Plus one. “This new approach analyzes the neural differences that contribute to the etiology of autism spectrum disorder.”
Building on the work of Alan Hodgkin and Andrew Huxley, who won the Nobel Prize in Medicine in 1963 for describing the electrochemical conductivity characteristics of neurons, Newman and his coauthors applied those concepts to understand how that conductivity differs in people with autism and in people without autism. , using the latest neuroimaging data and computational methodologies. The result is a first-of-its-kind approach to calculating the conductivity of neuronal axons and their ability to transport information through the brain. The study also provides evidence that those microstructural differences are directly related to participants’ scores on the Social Communication Questionnaire, a common clinical tool for diagnosing autism.
“What we’re seeing is that there is a difference in the diameter of microstructural components in the brains of autistic people that may cause them to conduct electricity more slowly,” Newman said. “It is the structure that limits the functioning of the brain.”
One of Newman’s co-authors, John Darrell Van Horn, a professor of psychology and data science at UVA, said that very often we try to understand autism through a collection of behavioral patterns that may be unusual or seem different.
“But understanding those behaviors can be a little subjective, depending on who is observing,” Van Horn said. “We need greater fidelity in terms of the physiological metrics we have so we can better understand where those behaviors come from. This is the first time this type of metric has been applied in a clinical population and sheds some interesting light on the origins of the TORCH.”
Van Horn said a lot of work has been done with functional magnetic resonance imaging, looking at signal changes related to blood oxygen in autistic individuals, but this research, he said, “goes a little further.”
“It’s not about asking if there is a particular difference in cognitive functional activation, but about how the brain actually conducts information around it through these dynamic networks,” Van Horn said. “And I think we’ve been successful in showing that there is something that is uniquely different among individuals diagnosed with autism spectrum disorder compared to typically developing control subjects.”
Newman and Van Horn, along with co-authors Jason Druzgal and Kevin Pelphrey of the UVA School of Medicine, are affiliated with the National Institutes of Health’s Autism Center of Excellence (ACE), an initiative that supports large-scale multidisciplinary, multi-institutional projects. scale. studies on ASD with the aim of determining the causes of the disorder and its possible treatments.
According to Pelphrey, a neuroscientist and brain development expert and principal investigator of the study, the overall goal of the ACE project is to lead the way in developing a precision medicine approach to autism.
“This study provides the basis for a biological target to measure treatment response and allows us to identify avenues for the development of future treatments,” he said.
Van Horn added that the study may also have implications for the screening, diagnosis and treatment of other neurological disorders such as Parkinson’s and Alzheimer’s.
“This is a new tool for measuring the properties of neurons that we are particularly excited about. We are still exploring what we could detect with it,” Van Horn said.