A new study points to a hidden trigger behind autism, and it has nothing to do with the part of the brain scientists always blamed

For years, neurodevelopmental research has focused on the cerebral cortex when trying to understand the roots of autism, since it is the brain region most associated with complex thinking, learning, and processing. A major study published in the journal Translational Psychiatry is now shifting that focus toward a different region entirely. The story, as reported by Bored Panda, detailed how researchers at Japan’s Kanazawa University identified the cerebellum as a possible hidden trigger for many of the social challenges associated with autism spectrum disorder.

The team focused on perineuronal nets, or PNNs, which are lattice-like supportive structures that wrap around cerebellar neurons and help maintain communication across the brain networks that govern social behavior. When researchers examined two mouse models of autism, one induced by prenatal exposure to valproic acid and another carrying a mutation in the CHD8 gene, they found a significant loss of these PNNs in the cerebellum.

To test whether this loss directly caused behavioral changes, the team deliberately disrupted PNNs in healthy mice. The mice began to show reduced social interaction and a lack of interest in unfamiliar peers, behaviors commonly associated with autism spectrum disorder.

Researchers say the findings point to a structural cause rather than a purely cognitive one

When researchers examined the underlying mechanism, they found that in healthy mice, social interactions normally activate cerebellar neurons that send signals to other brain regions responsible for processing social information. When PNNs were damaged, this neural activity dropped significantly, and communication between these brain networks weakened.

The team also identified a molecular player called ARNT2, a protein whose levels spiked when PNNs were lost, making affected neurons less responsive. Reducing ARNT2 activity restored normal brain function and social behavior in the mice, suggesting that autism related social difficulties may stem from a structural issue in the cerebellum and the circuits it controls, rather than solely from the brain’s higher level thinking centers.

This research arrived two days before a separate study published in Nature Neuroscience on May 15, 2026, led by the Instituto Italiano di Tecnologia in Rovereto, Italy, and the Child Mind Institute in New York. That study analyzed brain scans from 20 mouse models and more than 2,000 human participants, including children and young adults with autism as well as neurotypical individuals, to look for patterns in brain communication.

Researchers identified two distinct biological subtypes of autism in that analysis. The first is a hypoconnectivity group, where brain activity is reduced and linked to genes involved in synaptic junctions. The second is a hyperconnectivity group, characterized by increased connectivity and linked to immune system genes, with patients in this group showing measures of slightly more severe autism.

Seeing the same patterns across both mice and humans suggested to researchers that these are genuine biological subtypes rather than random variation, raising the possibility of more personalized diagnosis and treatment approaches if the findings hold up in further research. This is not the first attempt to categorize autism into distinct types.

A study from July 2025 involving researchers from Princeton University, the Simons Foundation, and the Flatiron Institute previously identified four types of autism by examining more than 230 behavioral characteristics in a group of 5,000 children. The researchers behind the connectivity study made their data and analysis tools publicly available for other scientists to review.

Further research is still needed to confirm whether the cerebellar mechanisms identified in mice apply directly to humans, but both studies point toward a more detailed, biologically grounded understanding of autism than previous models offered. This is a sensitive topic for many families, and anyone affected by autism spectrum disorder seeking guidance or support is encouraged to speak with a healthcare provider.

Claims about biological mechanisms tend to travel quickly once they reach social media, a pattern also seen recently when a viral 36-hour fasting video sparked its own scientific scrutiny over what the body actually does hour by hour. Online reactions to unconventional health and wellness claims have ranged just as widely in other contexts, including when a viral sea salt snack trend drew a flood of medical warnings after spreading widely online.