How Autism Affects the Brain?

When we think of the most important organ in our body, many organs may come to our minds. But if we question it from the logic frame, the most important organ is the one that is hidden in the most sheltered place. Just like jewels hiding in the case. It’s like the brain in the skull.

As far as we know, the brain is very soft and settled in a hard skull. It is the center of all our perceptions, thoughts, feelings, and everything. The brain is the most complex organ in the human body. Even more, it is probably the most complex entity present in this universe. The wonders created by the people, who are the perfect creatures in the world, are the result of the human brain and this result is the most important feature that makes people unbelievable and surprising.

You can be sure that this piece of meat is the most complex thing we can see in the universe. When you ask neuroscientists, some of them like to use that expression; ”The brain is survival equipment for human beings.“

It includes a number of programs and equipment in order to survive. Its main function is to keep human beings alive in daily life and to make things easier for us.



One of the most fascinating discoveries in the last couple of years is how much the human brain changes across the life span. There is tremendous variability in the development and aging of the brain and in related cognitive, emotional, and behavioral functioning.

Sometimes there will be dysfunctions in the brain. Brain dysfunction in either childhood or older age can be understood only in the context of what is typical or functional for individuals. Autism Spectrum Disorder is one of the neurodevelopmental disorders which typically arise first in childhood.

In this article, I will try to explain what Autism Spectrum Disorder (ASD) is and contributors to ASD. Then I move on to how autism affects the brain, especially what the reasons are behind that. As a conclusion, I will try to sort out what the relationship between autism and brain is.

Autism Spectrum Disorder (ASD)


Autism Spectrum Disorder is classified as a neurodevelopmental disorder by DSM – 5. It is mainly characterized by impairments in social interaction, communication, and stereotyped behaviors and interest.



For the diagnosis of ASD, symptoms should occur in early childhood. It is important to note that there is a wide variation in the severity and outcome of this disorder.

Children with ASD often do poorly of measures of intellectual ability, such as IQ tests. The deficits are confined to skills that require language and understanding other’s points of view. Again, we can say that it is related to impairment in social interactions. They may score in the average range on tests that do not require language skills.

Contributors to Autism Spectrum Disorder


Over the years, researchers claimed lots of theories about the causes of autism. In the beginning, researchers said a combination of biological factors and poor parenting. However, over the decades, researches showed that parenting has little or no effect on developing this disorder. Because it comes with birth.



Researchers implicated several biological factors in the development of ASD. Abnormalities in several genes have been associated with this disorder.

Neurological factors play an important role in ASD. Children with autism have greater head and brain size than children without it.

How Autism Spectrum Disorder Affects the Brain?


The impairments in language, social life, and emotional behaviors which are characteristics of ASD are associated with the brain. However, it is still unclear why the brain cannot be developed normally in the early periods of life.

Researchers claimed that ASD involves impairments in multiple brain areas or networks. Altered brain growth is observed, and most implicated are the frontal lobe, temporal lobe, especially the limbic system, and the cerebellum. Researchers call these parts “SOCIAL BRAIN” as a whole.



Neuroimaging studies showed a variety of structural abnormalities in the brains of people with ASD, including the cerebellum, cerebrum, amygdala, and hippocampus. On the other hand, neurological impairments could be the result of genetic factors.

Thanks to the fMRI scans, the researchers could confirm that in the brains of people with ASD, connections persist for more extended periods than they do in the neurotypically developed brains. In other words, in people with autism’s brains, the brain finds more difficult to switch between processes.

Brain connections disappear faster in normally developed brains, while they remain synchronized for up to 20 seconds in people with autism’s brains. Furthermore, in individuals with ASD, symptom severity appears to increase with connectivity duration.



While examining the brain structures, post-mortem examination, brain imagining, and other types of research methods are used. With regard to brain functioning, declined activity is observed in several regions such as frontal lobes and limbic system, especially in the amygdala.

The amygdala has an important role in the development of emotional memory and emotional responses, which means in social interactions. It is responsible for human beings’ behaviors such as fear, trust, and social relationship. Therefore, damage to the amygdala means that our lives will be adversely affected. That’s why we can be sure that individuals with Autism Spectrum Disorder have an impairment in the amygdala.

Since individuals with autism are toddlers, they have unusually large brain size. At birth, the brain would be normally developed, but after birth especially during the age of 2 – 4, atypical growth spurt occurs in their brains. Researchers supported this idea by measuring the head circumference.

Investigations showed that abnormalities in cell structure and organization occur in their brains. These could be a decreased number of cells and size of cells, high cell density, and abnormal cell migration. Also, these abnormalities might be developed in the womb, according to microscopic cell studies.



According to researchers, there are 4 main hypotheses behind the relationship between Autism Spectrum Disorder and the brain. They try to explain which one affects which one and how. These 4 hypotheses are;
• social motivation hypothesis
• overly intense world hypothesis
• theory of mind
• mirror neuron hypothesis

Social Motivation Hypothesis


As we know, the lack of social interaction is one of the core symptoms of ASD. For example, a child with autism is less likely to show other toys or to interact with other children or adults compared to a normally developed child.

The social motivation hypothesis proposes that it can be because of the brain’s reward system. As far as we know that social interactions are rewarding for human beings. The idea behind this hypothesis is that children with ASD do not find social interactions as rewarding as us, as normally developed people. It can explain why they are less likely to involve social interaction.

Researchers found that in their brains, there is a less reward-related brain activity that normally developed brains when the child anticipates communication. On the other hand, children with ASD have a larger approach and reward-related brain activity when providing non-social pictures compared to social ones.



As we know, children with ASD have restricted interests. These interests such as trains, ocean, electronics might be rewarding and social interactions might not be. That’s why maybe their rewarding systems work differently than normally developed individuals’ do.

Overly Intense World Hypothesis


The overly intense world hypothesis focuses on both social behavior and sensory symptoms. Children with autism might have too much brain activity, which makes it hard to selectively pay attention to some things and not pay attention to others. They experience the world as overwhelming and overly intense. That could explain why they often experience sounds as too loud or fabric and as too scratchy or rough.

In terms of social behavior, the overly intense world hypothesis explains why children with ASD have difficulties. As far as we know, people with autism are often overwhelmed by social interactions, which are unpredictable. The hypothesis considers that the root of both social deficits and sensory sensitivity in Autism Spectrum Disorder might be the same, which is over-responsivity in certain areas of the brain.



The areas of the brain might be over-active. These areas include the prefrontal cortex and the amygdala. The prefrontal cortex is where higher-order brain function happens. It means complex brain functions such as attention, memory, executive function and planning, and social cognition. 

Important functions such as regulation of body functions, related-oriented communication, emotion regulation, postponement of reactions, empathy, intuition, social skills, plan, control, logic, problem-solving, detailed thinking, management related to the prefrontal cortex. These functions are mostly impaired in individuals with autism.



The amygdala is important for interpreting and understanding emotionally important and related things in the environment. In ASD, over-activation in the amygdala is potentially related to their understandings. These individuals are not involved in social interactions as mus as normally developed people do. They find social situations unpleasant, or even aversive because the amygdala is mostly related to fears and phobias.

In addition to that information, individuals with ASD may have amazing memories. They are able to notice extremely small and important details, or perfect pitch compare to normally developed individuals.

Theory of Mind (ToM)


It is important to note that developing a theory of mind is a vital stage of child development. It refers to the ability to understand other people, the thoughts, and feelings. Also, it is the ability to figure out, recognize, and give meaning to the mental states of other people and ability to understand they may differ from our own. If a person can develop that very well, it helps people in most of the cases to save them in daily life such as solving conflicts, developing social skills, and giving meaning to other people’s behavior. 

Children with neurodevelopmental disorders have trouble answering some questions correctly until they are 3 or 4 years old. They assume that everyone knows what they know. Furthermore, there is behavioral evidence that the theory of mind is delayed in children with ASD.



Children with ASD have trouble understanding others. It causes social skills deficits, as we can understand. For example, think about that If you have difficulty to imply what other people are thinking and feeling, it would be hard to predict the reasons behind people’s behaviors. It makes social interactions and communications more stressful and confusing. As well as it leads to uncomfortable social interactions between individuals with autism and other people.

Impairments in the theory of mind could be the core of many of the behaviors associated with ASD. For example, limitations may lead to misreading or failure to read and understand emotions, intentions, feelings, or cues from others, basically impairments in empathy. 

In addition, people with autism have limited expression of empathy toward others, as we mentioned above, because of the challenges of the theory of mind. Deficits may also result in problems in social situations with assumptions that may not be accurate. As a result of having that kind of challenge selecting on cues from the social environment, reciprocity, such as the give-and-take, mutual benefit of a relationship, may be impacted.

Mirror Neuron Hypothesis


Mirror neurons are brain cells that are active when we perform actions. Whenever you do something, your mirror neuron cells activate. An interesting part of this neuron’s activities is, it is not only when a person performs an action, however, also when the person observes someone else moves. That’s why it is called a “mirror” neuron.



For example; when you see someone smile, the reason why you smile immediately is mirror neurons because your mirror neurons for smiling fire up, start to work. And then, they create a sensation in your own mind, associate own feeling with smiling. You experience the meaning of smiling immediately and effortlessly.

These neurons help as well as with copying other’s behaviors by imitating them. Imitation means copying the actions of others and it is a very important way in order to learn. Mirror neurons might help us “translate” the actions of others to our own perspective. It means when you observe someone’s action, you act like them in your way. It does not require the same types of equipment or tools, only it should be the same action.

For example, boys imitate their fathers when they shave, but they use their toys instead of a blade. Also, girls imitate their mothers when they have make-up, but they use their toys instead of real make-up stuff.



For investigating ASD, researchers pay attention to mirror neurons over time. Because according to some researches, they showed that mirror neuron activity is altered in children with autism. It causes them to have trouble in order to understand others’ actions.

For example, let’s say there is a child with autism and you show him the pictures of people while doing goal-directed actions. Even though they don’t have any problem saying what the person in the photo is doing, when it comes to saying the reason why the person in the picture was doing the action, they made errors. Automatic imitation which is mirroring does not happen when children with ASD observe actions in the environment.

Overall, individuals with autism would struggle to predict, understand, give meaning, or imitate the actions of others. Basically, they have problems with empathy. This would make social interactions confusing and unpredictable, which is one of the main symptoms of Autism Spectrum Disorder.

Recent Content