Autism’s Neurobiology: Brain Structure, Connections, And Neuronal Patterns

academicmemories
Aug 9
5 min read

By: Lea Kallo

Edited by: Annette Dao

Why I Picked This Topic

When I first started learning about autism, I realized I didn’t want to stop at just understanding surface-level traits or stereotypes. I wanted to know what was actually happening in the brain—how structure and wiring might help explain the experiences and behaviours of people on the spectrum.

Even though I don’t have a personal connection to autism, I’m fascinated by how the brain shapes how we think, feel, and interact. And the more I learned, the more I realized how much research has already been done—along with how much we still don’t know. Understanding the science behind autism can help us move away from labels and toward more supportive, inclusive environments that respect different ways of experiencing the world.

What the Research Says About the Autistic Brain

There’s no one “autistic brain”—just like there’s no one kind of autistic person. But researchers have found several consistent patterns that show up in brain development, structure, and connectivity. By looking at these patterns across studies, we can start to understand why certain behaviours, traits, or strengths are more common in people with autism.

Below is a breakdown of three studies that helped me make sense of how autism affects the brain—and how that might connect to real-life experiences.

1. Brain Growth and Early Overdevelopment

In a 2005 paper, researchers Eric Courchesne and Kathleen Pierce explored how autism affects early brain growth and organization. Their research focused especially on the association cortex, which is involved in higher-level functions like language, social thinking, and decision-making. They found that many children with autism show unusually rapid brain growth in the first few years of life—especially in these complex processing areas.

At first, this might sound like a good thing. But according to Courchesne and Pierce, the issue isn’t just how fast the brain grows, but how it organizes itself. In autism, early overgrowth can lead to an excess of neurons and brain connections—but those connections might not form in the right patterns. Instead of being well-organized, the brain may become chaotic or overloaded in some areas, especially those that handle social communication and flexible thinking.

This helps explain why some of the core traits of autism—like difficulty with social cues, speech, or multitasking—could be linked to brain growth that’s not following a typical path. The brain is working hard—but not always efficiently.

2. Brain Connectivity: Too Much Local, Not Enough Long-Distance

While Courchesne and Pierce focused on structure, a 2016 review by Aboitiz, Billeke, and Aboitiz looked at connectivity—how well different parts of the brain talk to each other. Using studies that relied on tools like fMRI and EEG, the researchers found that many people with autism show unusual patterns in how their brain is wired.

One of the main ideas is that local connectivity—communication between brain areas that are close together—is often higher than usual. But long-range connectivity, especially between far-apart regions like the front and back of the brain, is reduced. This means the brain may be very active in specific areas, but not as coordinated across larger networks.

This wiring pattern can help explain why autistic individuals might focus intensely on details but struggle with bigger-picture thinking or switching between tasks. Their brains are highly active—but not always balanced. The review also points out that connectivity patterns can vary by age, meaning these differences may shift as someone gets older.

Researchers used brain imaging tools like fMRI and EEG to study how different areas of the brain talk to each other.

fMRI, or functional magnetic resonance imaging, shows which parts of the brain are more active by tracking changes in blood flow. Basically, it lets scientists see where the brain is lighting up during certain tasks.

On the other hand, EEG (electroencephalography) looks at the brain’s electrical activity using sensors on the scalp. It’s great for showing when brain activity happens and whether it’s fast, slow, or out of sync.

Both of these tools helped the researchers figure out that people with autism tend to have weaker connections between distant brain regions and stronger connections between nearby ones. That could explain why some autistic people are amazing at focusing on small details but might struggle with big-picture thinking or switching between tasks.

3. Specific Brain Structures and Their Role in Autism

Not all research papers are packed with complex stats. Nicholette Zeliadt’s article from Spectrum News does a great job breaking down the brain differences seen in autism into terms that are easier to understand, while still being based on real science.

Zeliadt explains how several major brain regions are affected in autism:

Amygdala: This area helps regulate emotions. Some studies show it’s enlarged in young autistic children, which might be linked to stronger or more intense emotional responses.
Corpus callosum: This structure connects the two halves of the brain. In many people with autism, it’s smaller than average, which may make communication between hemispheres less efficient.
Cerebellum: Best known for movement and coordination, this part of the brain also plays a role in attention and social behavior. It often appears smaller or differently shaped in people with autism.
Cortex: The outer layer of the brain sometimes shows unusual folding patterns or thickness in children with autism, especially in areas related to speech and social reasoning.

These structural changes help connect what we see in behaviour (like sensory sensitivity, repetitive movement, or emotional overload) to what’s happening under the surface.

Why This Matters

Understanding autism through the lens of brain science doesn’t mean trying to “fix” anything. Instead, it shows us that autism is a different way of being—a different brain style, not a broken one. This kind of research helps shift the conversation from deficits to neurodiversity, where brain differences are seen as valuable and worth accommodating.

When we understand how brain growth and connectivity influence behaviour, we become more capable of meeting autistic individuals with empathy, not judgment. It also helps parents, teachers, doctors, and communities build better supports that actually match how autistic brains work.

Looking Ahead

Autism research is still growing. Brain imaging is becoming more advanced, and new discoveries are constantly being made. But even now, the findings are already helping us understand how brain differences shape behaviour, learning, and interaction.

And most importantly, this science reminds us that what we see on the outside is just one part of the story. Underneath every autistic trait is a brain doing its best to make sense of the world—just in its own way.

References

Aboitiz, V. A., Billeke, D., & Aboitiz, F. (2016). Brain connectivity in autism spectrum disorder. Frontiers in Psychiatry, 7, Article 107. https://doi.org/10.3389/fpsyt.2016.00107

Courchesne, E., & Pierce, K. (2005). The new neurobiology of autism: Cortex, connectivity, and neuronal organization. Current Opinion in Neurobiology, 15(2), 225–230. https://doi.org/10.1016/j.conb.2005.03.003

Zeliadt, N. (2020, November 16). Brain structure changes in autism, explained. Spectrum News. https://www.thetransmitter.org/spectrum/brain-structure-changes-in-autism-explained