The “Little Brain” & It’s Big Influence

(Applied to autism, cerebellar injury could hinder how other areas of the brain interpret external stimuli and organize internal processes. Based on a review of existing research, the researchers found that a cerebellar injury at birth can make a person 36 times more likely to score highly on autism screening tests, and is the largest uninherited risk. Credit: Samuel Wang)

As researchers dig into the root causes for autism, they are finding that our cerebellum or “little brain” may play a bigger role in shaping our cognitive and language abilities than previously thought, especially in the prenatal phase. The cerebellum actually only makes up a total of 10 percent of our brain’s mass, but is the home of 50 percent of it’s neurons. The cerebellum is usually associated with movement and coordination, so a doctor checking for damage in the cerebellum would conduct a number of tests that check balance and motion. However, a recent study published in the journal Neuron suggests that dysfunction in the cerebellum in crucial moments during development could be one of the leading contributors to autism spectrum disorders as well as other neurodevelopmental disorders.

Dr. Samuel Wang, associate professor of molecular biology and neuroscience at Princeton University, and his research team, put forward the theory that the cerebellum is not only responsible for movement but also for helping developing minds process more complex sensory information that also aids in establishing social bonds. He explains, “Some of the clinical and animal-research evidence for cerebellar involvement in autism has been known for years, but this evidence doesn’t fit into the textbook wisdom that the cerebellum controls sensory processing and movement. At some level, researchers have been trapped by whatever framework they learned in college or grad school.”

In their study, Dr. Wang found that for children who experience damage to their cerebellum at birth are at an increased risk for ASD that he shows is comparable to the risk of a smoker developing lung cancer. So how is the cerebellum connected to developing “higher functioning” social and language capabilities? The study explains that a baby seeing their parent smile will eventually connect that experience to certain rewards that come along with it, for example being fed, which would overtime lead to the child’s ability to understand these social cues—a connection that is facilitated by the cerebellum. These connections that will eventually help with social behavior are especially vulnerable in the prenatal environment.

In Dr Wang’s words, “because the risk factor from cerebellar injury is bigger than any other know environmental risk, we think this provides deep insight into the basic biology of how ASD brains go off track. Problems in cerebellar function aren’t the (only) cause of autism, but they are potentially a significant cause of autism.” 

Studies like this one are important in developing best practices for treatment and therapy for those on the spectrum. Another recent clinical study published in the American Academy of Pediatrics issued new guidelines for physicians in diagnosing specific intellectual and developmental disabilities. The report argues that it is important to know the root of the child’s disability whenever possible in order to find the most appropriate treatment plans. Moreover, a better diagnosis will help families manage expectations and advocate for their child in the best way possible.