Inside the Neurodivergent Brain: What Brain Imaging Reveals
While the terms “neurodivergent” and “neurodiversity” are not new, they’ve gained significant traction in recent years. Still, many people harbor confusion about their exact meaning and the conditions they describe.
Diagnoses for neurodiverse conditions such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD)—also called attention deficit disorder (ADD)—are on the rise. At the same time, growing research and awareness are helping to shed light on other neurodiverse traits, such as dyslexia, and how they affect thinking, learning, and behavior.
With increased awareness, we now recognize that these brains are simply wired differently. At Amen Clinics, we’ve seen this firsthand. For decades, we’ve used functional brain scans with SPECT (single photon emission computed tomography) to reveal the unique activity patterns that distinguish neurodivergent brains from neurotypical brains.
For decades, Amen Clinics has used functional brain scans with SPECT (single photon emission computed tomography) to reveal the unique activity patterns that distinguish neurodivergent brains from neurotypical ones.
UNDERSTANDING THE NEURODIVERGENT BRAIN
Since the 1970s, SPECT scans have helped medical experts understand how the brain works. Today, this state-of-the-art imaging tool evaluates blood flow and activity in different regions of the brain. SPECT shows what areas of the brain are working well, too hard, or not hard enough.
Meanwhile, the terms neurodivergent and neurodiversity have been used since the 1990s. They are frequently credited to Australian sociologist Judy Singer, as well as (in more recent research) to the collective of neurodivergent people themselves. Neurodivergence refers to brains that developed differently.
As the U.K.-based organization ADHD Aware points out, neurodevelopmental conditions like ADHD and ASD present symptoms, behaviors, and traits that result from these developmental differences. They can occur before birth or in the early stages of childhood.
This distinguishes neurodivergence from a mental health condition. In the latter, patterns of behavior or state of mind deviate from the “normal self.” But neurodevelopmental conditions denote a different “normal” altogether.
ADHD Aware adds that the roots of neurodevelopmental conditions may be found in:
- Genetics
- Trauma at birth
- Infectious diseases
- Immune disorders
- Nutrition
- Physical trauma
While these brains work differently, they can also have unique strengths. Let’s look at some ways neurodiversity can affect brain function, according to findings from SPECT scans at Amen Clinics.
Related: The ABCs of the Human Immune System
FUNCTIONAL BRAIN DIFFERENCES IN ADHD
An estimated 7 million (11.4%) U.S. children from ages 3-17 had ever been diagnosed with ADHD in 2022, according to the Centers for Disease Control (CDC). That reflects a 1-million increase compared to statistics compiled in 2016.
Over decades of performing brain scans, Amen Clinics has determined that there are actually seven types of ADD. Each has its own unique set of symptoms, but generally ADHD brains show differences when trying to concentrate.
In the neurotypical brain, concentration would increase blood flow in certain regions—especially in the prefrontal cortex (PFC). This region is key in planning, focus, organization, and follow-through.
Healthy Neurotypical Brain SPECT Scan
However, during moments of concentration, people with ADHD will experience a blood flow decrease in the PFC. Trying harder to concentrate actually makes the task more difficult.
Related: What Is the Executive Center of the Brain
Here is an overview of differences in brain function for each of the seven types of ADHD:
Type 1: Classic ADD is often called ADHD, due to the presence of hyperactive behavior. Hallmark traits include being inattentive, easily distracted, and restless or fidgety.
Classic ADD Neurodivergent Brain SPECT Scan
Type 2: Inattentive ADD, the second most common type, is associated with being quieter, more introverted, and prone to daydreaming. These individuals can also have trouble focusing but don’t usually show the behavior problems that characterize Classic ADHD.
In Types 1 and 2, the brain appears normal at rest. But during times of concentration, there tends to be decreased activity in the underside of the PFC, as well as in the cerebellum and basal ganglia.
Type 3: Overfocused ADD relates to difficulties with shifting attention. Brain scans show increased activity, even at rest. Increased activity occurs in the anterior cingulate gyrus (the brain’s “gear-shifter”), while decreased activity affects the underside of the PFC, the cerebellum, and the basal ganglia.
Type 4: Temporal Lobe ADD can create issues with learning and memory, unstable mood, and aggression. SPECT scan findings highlight decreased (and occasionally increased) activity in the temporal lobes, both at rest and during concentration.
Concentration also triggers decreased activity in the underside of the PFC, the cerebellum, and the basal ganglia.
Type 5: Limbic ADD involves an underactive prefrontal cortex during concentration, while the deep limbic area (involved with mood) is overactive. SPECT scans typically show increased deep limbic activity at rest, and decreased activity in the PFC, cerebellum, and basal ganglia during concentration.
Type 6: Ring of Fire ADD is associated with overall high activity in the brain, which can lead to overwhelming thoughts and emotions. These patchy areas of increased activity often affect multiple areas of the brain, creating a “ring” shape, but patterns can vary from person to person.
Type 7: Anxious ADD corresponds with areas of low activity as well as overactivity—and the resulting anxiety can aggravate ADHD symptoms. Brain scans show increased activity in the basal ganglia at rest and during concentration. In the PFC and cerebellum, activity decreases during concentration.
WHAT DO BRAIN SCANS FOR AUTISM SHOW?
Like ADHD, autism diagnoses are also increasing. According to the CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network, about 1 in 31 (3.2%) 8-year-old children had been identified with autism spectrum disorder in 2022. In 2020, that number was 1 in 36.
Any of the following symptoms, ranging from mild to severe, can accompany ASD:
- Deficiencies in social and communication skills
- Limited and repetitive behaviors and interests
- Developmental disabilities, including intellectual and language impairments
The differences in early brain development associated with ASD relate to the way neurons communicate with one another. This can lead to a variety of issues, including difficulty performing everyday tasks.
However, ASD does not point to a single brain problem in adults and children. In fact, a suspected eight to 10 factors can influence abnormal brain function and lead to this type of neurodivergence.
Brain-imaging studies of people with autism reveal that their brain patterns tend to have areas of high activity, low activity, or areas of both. Abnormal activity often affects the cerebellum, anterior cingulate gyrus, amygdala, and the temporal, frontal, and parietal lobes.
Therefore, there are high and low activity patterns in ASD. High activity patterns describe increased activity in the anterior cingulate gyrus and lateral prefrontal cortex. This is linked to symptoms such as repetitive speech and behavior. Increased activity in the brain can also contribute to mood instability or anxiety.
Low activity patterns, meanwhile, tend to accompany a smaller, less active cerebellum. This is associated with diminished motor skills and problems with learning and thought coordination. Overall, the surface of the brain, as well as the parietal and temporal lobes, have decreased activity, affecting communication, language, and social skills.
Autism Brain SPECT Scan
OTHER FORMS OF NEURODIVERGENCE
In addition to ADHD and autism, neurodivergence can take numerous other forms. Here are some of the most common types:
Dyslexia, which describes reading impairment and affects about 20% of the population. SPECT scans of individuals with dyslexia often show decreased activity in two brain regions: the prefrontal cortex and the left temporal lobe.
Dyslexia is a type of specific learning disorder (SLD), a grouping that includes other neurodivergent conditions, such as:
- dysgraphia (writing impairment)
- dyscalculia (math impairment)
The American Psychiatric Association (APA) estimates that 5-15% of school-age children have a learning disability.
Dyspraxia, also called developmental coordination disorder (DCD), affects motor abilities. In the past, researchers struggled to pinpoint its best diagnosis and management. Today, while more research is still needed, studies have linked several brain areas to this condition: the cerebellum, basal ganglia, parietal lobe, and parts of the frontal lobe.
The APA defines neurodiversity as a “concept that regards individuals with differences in brain function and behavioral traits as part of normal variation in the human population.” Therefore, this definition includes, in addition to all of the above:
- Dysphonia (disorders affecting the voice)
- Tourette syndrome
- Synesthesia (the linking of two senses, such as sight and sound)
- Other behavioral and neurobiological differences
THE IMPORTANCE OF BRAIN IMAGING IN NEURODIVERGENCE
Neurodivergence can easily be misdiagnosed or simply remain untreated. And, because disorders like autism and ADHD are complex and assume multiple forms, brain imaging is instrumental in guiding accurate diagnosis and effective, targeted treatment plans.
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Through improved understanding of the neurodivergent brain and neurodivergent thinking, mental health professionals can provide brain-based interventions to minimize this growing population’s challenges and optimize its strengths. The ultimate goal is to best equip neurodivergent individuals for success—regardless of their differences.
Amen Clinics
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ADHD Aware. What Is Neurodiversity: Neurodevelopmental Conditions. https://adhdaware.org.uk/what-is-adhd/neurodiversity-and-other-conditions/
American Psychiatric Association. Exploring a Strengths-Based Approach to Neurodiversity. April 11, 2022. https://www.psychiatry.org/news-room/apa-blogs/exploring-a-strengths-based-approach-to-neurodiver
CDC. Data and Statistics on ADHD. November 19, 2024. https://www.cdc.gov/adhd/data/index.html
CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network. Data and Statistics on Autism Spectrum Disorder, May 27, 2025. https://www.cdc.gov/autism/data-research/index.html
APA, What Is Specific Learning Disorder? https://www.psychiatry.org/patients-families/specific-learning-disorder/what-is-specific-learning-disorder
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