Interactions between cortical and subcortical brain areas play a role in hypersensitivity in people with ASD

Heightened interactions between the cortical and subcortical brain areas show that hypersensitivity to stimuli plays a central role in people with Autism Spectrum Disorder (ASD). This is the conclusion reached by research by the team of Christian Keysers and Leonardo Cerliani of the Netherlands Institute for Neuroscience. The discovery is the key to understanding the often underestimated hypersensitivity in autism. The research was published in JAMA Psychiatry on 10 June 2015.

People with ASD are known for their unusual behavior in a social environment. They also show traits that may be linked to a heightened sensory perception. For instance, people with ASD can hear very soft sounds from a distance and are able to spot tiny details in a photograph. However, this hypersensitivity is not necessarily a gift. “The numerous sensory stimuli we constantly receive may be distracting and sometimes even overwhelming. It prevents us from focusing on what is really important,” says Cerliani. With their research, the scientists show that heightened interactions between certain brain areas are at the root of this hypersensitivity.

Brain activity

Brain regions that are strongly coupled show synchronous brain activity, even in rest, while the brain activity in independent areas fluctuates independent of each other. The project examined this synchronization of spontaneous brain activity. The results show that, in people with ASD, there is heightened synchrony between the part of the cortex that is involved in perception and the subcortical structure that passes sensory information on to the cortex. A higher synchrony tended to be accompanied by a higher severity of the autistic traits.

“During the development from childhood to adolescence, the interaction between brain areas changes, when it concerns spontaneous brain activity. A normal development sees the activity of the area involved in sensory perception, the cortex, become independent of the activity of the subcortical structure that passes the sensory information on to the cortex,” explains Keysers. “This change enables us to gradually learn how to block out irrelevant stimuli and to focus. People with ASD are unable to do this. Their sensory cortex appears to be abnormally coupled to subcortical structures.

Large research population

The project used the largest cohort of people with ASD to date, the ABIDE (Autism Brain Imaging Data Exchange) dataset. These MRI data have been collected by 17 international research centers and consist of 539 ASD patients and a group of 573 controls. The database was created and is coordinated by Dr. Adriana Di Martino, Dr. Stuart Mostofsky and Dr. Michael Milham. The Keysers and Cerliani team also contributed to the compilation of this database with neuroimaging data obtained by Dr. Marc Thioux.

Autism spectrum disorder

ASD is an umbrella name for a number of developmental disorders, including classic autism and Asperger syndrome. The number of people with ASD has grown 8-fold over the past twenty years and is seen in over 1% of all children.

For questions about this project please contact the authors.
Prof. Dr. Christian Keysers, e-mail: c.keysers@nin.knaw.nl tel: +31610110358
Prof. Dr. Leonardo Cerliani, e-mail: leonardo.cerliani@gmail.com tel: +33752938540