Sensory processing problems in autism: Mice reveal brain mechanisms, treatment potential

The following is from a post originally written for Vector, Boston Children’s Hospital’s science and clinical innovation blog.

A mouse study explores how sound and touch information come together in the autistic brain (Image courtesy of Nadine Gogolla)

Families of children with autism spectrum disorder have long noted sensory processing difficulties such as heightened sensitivity to noise, touch or smell—or even specific foods or clothing textures—earning sensory processing a place in the official DSM-5 description of the disorder.

“A high proportion of kids with autism spectrum disorder will have difficulty tolerating certain kinds of sensory inputs,” says Carolyn Bridgemohan, MD, co-director of the Autism Spectrum Center at Boston Children’s Hospital. Others, she adds, are less sensitive to certain stimuli, showing a higher tolerance for pain or excessively hot or cold temperatures.

A study published last week in Neuron uses mouse models to shed new light on the brain mechanisms that underlie sensory processing abnormalities in autism. Led by Takao K. Hensch, PhD, of the Department of Molecular and Cellular Biology at Harvard and the F.M. Kirby Neurobiology Center at Boston Children’s, researchers examined how the brain integrates sound and touch information in a deep brain region called the insula. In several studies of people with autism, the insula has come up as an area of abnormal activity or connectivity.

In normal laboratory mice, the insula’s response to simultaneous sound and touch is often stronger than the sum of its responses to each stimulus separately. However, in four separate mouse models of autism, Hensch and colleagues found that the insula’s response to sound and touch together was actually less than the sum of its parts. This abnormality in sensory integration correlated with an imbalance in “excitatory” versus “inhibitory” signaling between neurons in the brain—and it could be prevented when the excitatory-inhibitory imbalance was corrected early with medication.

“Despite ample evidence in humans that the insula is deeply involved in hallmarks of the social brain, such as empathy, pain and urges, this is the first attempt to characterize its development in an animal model of autism,” says Hensch, also a member of the Center for Brain Science at Harvard and director of the Conte Center at Harvard, focused on developmental origins of mental illness.

Read the full story on Vector >>