Are Autistic Brains Different From Normal Brains?

Autism refers to a birth condition that impacts the brain development of people. Even though it is diagnosed based on two core behaviors present in a person, i.e., difficulty in social communication and interactions. 

This also includes restricted interests and repetitive behaviors, and communication difficulties. These characteristics are believed to occur in a person because of changes in how various parts of their brain have been formed and connected.

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There hasn’t been any major study that has identified a ‘typical’ brain structure for autism, which means that no pattern of abnormalities exists in all autistic individuals. 

Are Autistic Brains Different From Normal Brains?

The findings of research based on the brain anatomy of autistic people are frequently inconsistent since, generally, there is a lot of variation between people. 

However, for specific subsets of autistic persons, some tendencies have started to appear. These changes may allow us to understand how the brains of certain people with autistic work. They might also hint at specialized therapies for specific autism subgroups.

A brain scan ranging over 15 minutes can help in diagnosing autism. The information comes from research examining whether structural changes in the brain may be used to identify autistic individuals. 

Moreover, it was shown that a computer algorithm employing five distinct assessments of brain shape and structure through a brain scan might accurately diagnose autism in adults by almost 85 percent. 

According to the researchers, these data might be utilized as a “biomarker” for autism spectrum illnesses. As per another research, the brains of autistic individuals have several anatomical changes compared to the non-autistic ones.

The alterations can be found throughout the brain and not only in the affected areas. The results imply that autism affects several more brain areas than was initially believed. 

However, specific structural changes identified in patients with autism have been seen in brain scans of non-autistic people, suggesting that they aren’t the primary marker of the disorder.

The Difference In Brain Autism Parts

According to research, magnetic resonance imaging (MRI), a brain-scanning method, has shown a few anatomically unique brain areas in persons with autism.

Numerous studies also show that autistic people, both adults, and children, have a larger hippocampus, the part of the brain responsible for memory formation and storage. Yet, it is unclear if this difference remains throughout maturity.

Even though studies from various laboratories have found contradicting findings, the amygdala size appears to be different between autistic and non-autistic people. 

Certain studies had also discovered that autistic persons have smaller amygdalae than the non-autistic ones, and the latter group had smaller amygdalae just when they were suffering from anxiety. 

Other researchers have discovered that children with autism had a larger amygdala during earlier stages of development and that this variance, however, fades with time.

 A meta-analysis of several imaging studies revealed that people with autism have less brain tissue in certain cerebellum areas, i.e., the part of the brain near the skull base. This part has long been assumed to have a function in movement coordination, yet studies have now shown that it also contributes to social interaction and cognition functions.

Globally, both autistic and non-autistic people appear to have a varied pattern of cortex thickness, which is the brain’s outer layer. 

According to recent research, this distinction is linked to changes in a particular kind of neuron during a person’s growth.

Changes In Structural Differences During Growth 

As per extensive research, some newborns who have subsequently identified with autism exhibit rapid development in a few of the areas of their brain. 

Moreover, especially when they’re 6-12 months of age, children with autism have a much quicker increase in their brain’s surface area than their non-autistic counterparts. It has been seen that the volume of their brain grows substantially quicker than other children without autism during 2 years of age.

The findings back up the previous study that found more giant skulls and brains in a subset of people with autism. Their brain appears to develop too fast during the initial stages of childhood, even before behavioral signs of the condition may be recognized. 

Neurotypical brains keep on developing in size until later phases of childhood, but they start to shrink during maturity. The brains of specific autistic individuals, on the other hand, begin shrinking before they reach their mid-twenties.

Compared to others without autism, confident children who are subsequently identified with autism have more cerebrospinal fluid, the liquid surrounding the brain, which might lead to a giant head. 

Those with the most flexible personalities are more likely to develop autistic symptoms later in their lives. Excess fluid can be seen even during the first 6 months of a child’s life and can last until 39 years.

The Difference In Connection Structures With The Brain 

White matter, which refers to the bundles of neurons that connect different areas of the brain, appears to be changed in autistic persons as well. 

Diffusion MRI, a technology that monitors the movement of water across the brain, is commonly used for inferring the white matter structure.

People lacking a, or even all parts, of their corpus callosum, which is the tract of the white matter that links both hemispheres of the brain, are more likely to have autism or exhibit related symptoms. 

This is because several connections that run through the brain are found in this part, and if these are broken, the condition can cause autistic symptoms, which aligns with autism’s connectivity theory. 

Another recent study revealed that the organization of numerous white-matter tracts in children with autism differs significantly. White matter changes in the brain of autistic children and teenagers are also observed.

Differences Based On Gender

No study has made it clear if the gender of a person impacts the level of autism. This is generally because a smaller number of girls get diagnosed with autism compared to boys. Nonetheless, research has shown evidence of gender-based differences in autistic brains. 

Also, make sure to check out my post on How Can Autism Affect An Individual’s Physical Development?

For instance, the amygdala is more impaired in girls with autism than in their male peers. Thus, a larger amygdala is connected with more severe emotional issues.

White matter changes are different by gender in autistic children as well. Compared to the control group, girls with autism have a higher level of structural stability in their corpus callosum. In comparison, boys with autism have a lower level of structural stability.

Other anatomical differences have been seen to be almost the same among both genders, such as the pace of brain development and cerebrospinal fluid volume.