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Dynamic Clamp Methods to Investigate Impaired Neuronal Excitability Associated with Autism
Published on: October 17, 2025
Microglia in the cerebral cortex in autism
Nicole A Tetreault1, Atiya Y Hakeem, Sue Jiang
1Division of Biology, California Institute of Technology, 1200 East California Blvd, MC216-76, Pasadena, CA 91125, USA. nicolet@caltech.edu
Abstract:
We immunocytochemically identified microglia in fronto-insular (FI) and visual cortex (VC) in autopsy brains of well-phenotyped subjects with autism and matched controls, and stereologically quantified the microglial densities. Densities were determined blind to phenotype using an optical fractionator probe. In FI, individuals with autism had significantly more microglia compared to controls (p = 0.02). One such subject had a microglial density in FI within the control range and was also an outlier behaviorally with respect to other subjects with autism. In VC, microglial densities were also significantly greater in individuals with autism versus controls (p = 0.0002). Since we observed increased densities of microglia in two functionally and anatomically disparate cortical areas, we suggest that these immune cells are probably denser throughout cerebral cortex in brains of people with autism.
Insights
Autism is associated with increased microglia, or immune cells, in the brain. This study found significantly higher microglial densities in the fronto-insular and visual cortex of individuals with autism compared to controls.
Area of Science:
- Neuroscience
- Immunology
- Autism Spectrum Disorder Research
Background:
- Microglia play crucial roles in brain development and function.
- Alterations in microglial populations have been implicated in neurodevelopmental disorders like autism spectrum disorder (ASD).
Purpose of the Study:
- To investigate microglial densities in specific cortical regions of individuals with autism.
- To determine if increased microglial presence is a feature of autism in the cerebral cortex.
Main Methods:
- Immunocytochemistry was used to identify microglia in autopsy brain samples.
- Stereological quantification with an optical fractionator probe was employed to determine microglial densities.
- Analyses were conducted blind to subject phenotype.
Main Results:
- Significantly higher microglial densities were observed in the fronto-insular cortex of individuals with autism compared to controls (p = 0.02).
- Significantly greater microglial densities were also found in the visual cortex of individuals with autism versus controls (p = 0.0002).
- One individual with autism showed microglial densities within the control range and was a behavioral outlier.
Conclusions:
- The findings suggest increased microglial densities in distinct cortical areas in individuals with autism.
- These results support the hypothesis that microglia may be denser throughout the cerebral cortex in autism.
