What Part of the Brain Does Autism Affect?

Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects communication, behavior, and social interactions. Research links autism to differences in brain structure and function, influencing how individuals process information and respond to their environment. Understanding these neurological variations provides insight into the diverse experiences of those with autism.

Scientists have identified multiple brain regions involved in ASD, each contributing to different aspects of cognition and behavior.

Cerebral Cortex Regions

The cerebral cortex, responsible for higher-order cognitive functions such as reasoning, language, and sensory processing, plays a significant role in autism. Neuroimaging techniques like functional MRI and diffusion tensor imaging reveal structural and functional variations in multiple cortical areas among individuals with ASD.

Frontal Lobe

The frontal lobe governs executive function, decision-making, and social cognition—areas commonly affected in autism. A 2021 Nature Neuroscience study found altered connectivity between the prefrontal cortex and other brain areas in children with autism, potentially contributing to challenges in flexible thinking and impulse control. Differences in the orbitofrontal cortex, which regulates emotions and reward processing, have been linked to difficulties in recognizing social cues and managing emotions. Structural imaging also reports increased cortical thickness and abnormal neuronal density in this region, which may affect information processing speed and adaptability. These alterations likely contribute to the executive and social difficulties characteristic of ASD.

Temporal Lobe

The temporal lobe is crucial for language comprehension, auditory processing, and facial recognition—areas often impacted in autism. Neuroimaging studies consistently identify abnormalities in the superior temporal sulcus, a region involved in interpreting social stimuli like speech and eye contact. A 2020 Journal of Neuroscience study found reduced activation in this area when autistic individuals processed social interactions, which may explain difficulties in verbal and nonverbal communication. The fusiform gyrus, essential for facial recognition, shows differences in autistic individuals, leading to impairments in social engagement. Variations in the auditory cortex have also been linked to sensory sensitivities, contributing to sensory overload. These findings highlight the temporal lobe’s role in communication and perceptual challenges in autism.

Parietal Lobe

The parietal lobe integrates sensory information, regulates spatial awareness, and manages attention—functions that often present differently in autism. Structural MRI studies identify atypical gray matter volume in the inferior parietal lobule, a region involved in social cognition and theory of mind. A 2019 Cerebral Cortex study found reduced connectivity between the parietal lobe and sensory-processing regions, which may contribute to difficulties in coordinating multiple sensory modalities. Disruptions in the posterior parietal cortex have been linked to motor coordination challenges and variations in attention shifting, affecting focus and adaptability in dynamic environments.

Subcortical Structures

Beyond the cerebral cortex, several subcortical structures exhibit differences in individuals with autism. These deeper brain regions contribute to emotional regulation, memory formation, and motor coordination, all of which can be affected in ASD.

Amygdala

The amygdala processes emotions, particularly fear and social signals, and has been extensively studied in autism. Research reports differences in amygdala volume, with some studies noting enlargement in early childhood followed by a reduction in adolescence and adulthood. A 2022 Biological Psychiatry study found increased amygdala volume in autistic children, correlating with heightened anxiety and social difficulties. Functional MRI studies reveal altered amygdala activation in response to facial expressions, suggesting challenges in interpreting social cues. Disrupted connectivity between the amygdala and prefrontal cortex may further affect emotional regulation and decision-making.

Hippocampus

The hippocampus plays a key role in memory formation and spatial navigation, both of which can be affected in autism. Structural imaging studies report differences in hippocampal volume, with some findings indicating increased size in early development. A 2021 NeuroImage: Clinical study linked larger hippocampal volumes in autistic children to differences in memory processing and learning strategies. Functional studies also reveal altered hippocampal activity during episodic memory tasks, suggesting reliance on different neural mechanisms for recalling past experiences. Disruptions in hippocampal connectivity with the prefrontal cortex may contribute to difficulties in flexible thinking and adapting to new situations.

Basal Ganglia

The basal ganglia regulate motor control, habit formation, and reward processing—functions that can present differently in autism. Diffusion tensor imaging studies identify atypical white matter connectivity in this region, which may contribute to repetitive behaviors and motor coordination challenges. A 2020 Brain study found differences in striatal activity, a key component of the basal ganglia, during motor planning and reinforcement learning tasks. Variations in dopamine signaling within the basal ganglia have also been proposed as a factor influencing reward processing and motivation in autism.

Cerebellum Architecture

Once thought to primarily coordinate movement and balance, the cerebellum is now recognized for its broader role in cognition and behavior. Structural imaging studies consistently report differences in cerebellar volume and organization in autism, with some findings indicating an overall reduction in size and others noting specific alterations in particular lobules.

Postmortem analyses reveal a reduction in Purkinje cells—large inhibitory neurons that regulate information flow—suggesting disruptions in motor and cognitive processes. Functional MRI studies link cerebellar dysfunction in autism to difficulties in adapting to new information, contributing to repetitive behaviors and rigid thinking. Disruptions in cerebellar connectivity with the cerebral cortex and limbic system may further affect emotional processing and social interaction.

Connectivity Patterns Across Regions

How different brain regions communicate plays a significant role in autism, influencing cognitive flexibility, sensory processing, and social behavior. Functional MRI and diffusion tensor imaging studies consistently show altered neural connectivity in ASD. Some regions exhibit excessive local connectivity, which may enhance pattern recognition and focus, while long-range connections between distant brain areas are often weaker, potentially affecting complex information integration.

One of the most studied disruptions involves the default mode network (DMN), which governs self-referential thinking, social cognition, and introspection. Research finds reduced synchronization within the DMN, particularly between the medial prefrontal cortex and posterior cingulate cortex, which may contribute to difficulties in understanding others’ perspectives and adapting to social contexts. Meanwhile, heightened connectivity in task-related networks, such as the salience network, may explain why autistic individuals intensely focus on specific stimuli while struggling with broader contextual awareness.