When we drive a car, we make rational decisions like attaching a seatbelt for safety. That’s our thinking brain or new brain. But when we hit the gas pedal on a clear stretch of road, that’s the evolutionarily older brain taking over. The old brain is the seat of emotion, motivation and motor ability.
Most researchers have studied the new brain, the cerebral cortex, to gain insight into autism. But now a Calgary research team has shifted the attention to the old brain or the limbic system. It is novel research in this field to measure surface and shape in these deep brain structures within a large population diagnosed with autism. The study’s findings are recently published online in the journal Neuropsychopharmacology.
International collaboration makes large autism study possible
“Most autism brain research to date has focused on the parts of the brain's cortex involved in processing complex social information,” says the senior investigator, Signe Bray, PhD.
“But, when you recognize that people on the autism spectrum also show unique motor behaviours, differences in motivation and cognitive control, it starts to make a lot of sense to look at these deep brain structures that are so fundamental.” Autism spectrum disorder or ASD is a group of developmental disabilities that affects about 1 in 68 children in Canada, according to the National Epidemiologic Database for the Study of Autism.
Bray is the scientific director of the Child and Adolescent Imaging Research Program (CAIR) at the Alberta Children’s Hospital, an assistant professor in the departments of radiology and paediatrics at the Cumming School of Medicine, and an investigator at the university’s Alberta Children’s Hospital Research Institute (ACHRI).
The research team used data banked in a repository called the Autism Brain Imaging Data Exchange (ABIDE), a database with contributions from 17 different research labs worldwide. Using the databank, researchers could analyze the deep brain structures of 757 young adults, half of them diagnosed with autism and half without. The research team also collaborated with the Douglas Mental Health Institute at McGill University which developed the sophisticated data software to perform the analysis.
MRI technology advances research
The participants in the study submitted to magnetic resonance imaging (MRIs), a process in which pictures are taken of the brain by radio waves and magnetic fields, giving different information than what can be seen with X-ray, ultrasound or even computer tomography. The study was performed by Manu Schuetze, a PhD candidate in the neuroscience graduate program and trainee under the ACHRI trainee program supervised by Bray.
Schuetze studied the shape of the thalamus, striatum and pallidum, organs found deep in the sub-cortical sections of the brain. Some of these organs were only first recognized as distinct anatomical structures in the last 35 years, so their shape, volume function and development are still being discovered. Most researchers have studied the size of these sub-cortical structures. But this study reveals there is a difference in regional shape — and not overall volume for those with autism.
Shape matters more than size: study
“While our study shows that deep brain structures of people with autism don’t differ from people without autism in their size, we found that some of them did differ in their shape. This is very exciting because looking at shape is a relatively new and potentially more sensitive way of investigating brain structure," Schuetze says.
“Our findings are interesting, because we know that for example, the front part of a deep brain structure communicates with a different area in the cortex than the back or side parts of it. Understanding which exact parts have developed differently and hence communicate differently with the cortex, can help us draw a better picture of the neurobiology of autism symptoms."
Obtaining an improved scanned image of the deep brain structures is possible because of new technologies, allowing a much clearer understanding of the brain and its functions. “The technologies for acquiring and processing MRI images are improving daily, making studies like these which rely on building a three-dimensional model of the brain’s structures possible for the first time,” says Bray, who did her post-doctoral training at the Center for Interdisciplinary Brain Sciences Research at Stanford University.
Learn more about study
The Bray research team is currently conducting studies to measure the function of the deep brain structures. They are looking for children aged 3-7 years and 14-20 years, with and without autism.
For more information on participating in autism studies at the University of Calgary, visit asdbrainresearch.ca, MRI4Kids.ca and hiccupkids.ca. This research was funded by a Sick Kids Foundation Young Investigator award to Dr. Bray and an ACHRI-CIHR Training Award to Manuela Schuetze.
The HBI-led Brain and Mental Health research strategy provides a unifying direction for brain and mental health research at the University of Calgary. This exciting strategy positions University of Calgary researchers to unlock new discoveries and treatments for brain health in our community by working in interdisciplinary teams.