TL;DR
Yale researchers used MRI and PET scans to compare the brains of 16 autistic adults and 16 neurotypical controls and report lower availability of the metabotropic glutamate receptor 5 (mGlu5) across autistic participants. EEG measures in most autistic participants were associated with this reduced receptor availability; researchers say the result may inform future diagnostics and treatments but causal direction is not established.
What happened
Scientists at Yale School of Medicine scanned 16 autistic adults and 16 neurotypical adults with MRI and positron emission tomography (PET) to map anatomy and molecular function. PET imaging showed lower brain-wide availability of the metabotropic glutamate receptor 5 (mGlu5) in the autistic group. Fifteen autistic participants also completed electroencephalography (EEG); the team found correlations between EEG electrical measures and the reduced mGlu5 signal. Authors interpret the result as supporting hypotheses that an imbalance between excitatory and inhibitory signaling is relevant to autism. The study population consisted of adults with average or above-average cognitive ability. Investigators note PET’s cost and radiation exposure limit its broader use and are developing lower-exposure PET methods to enable future studies in children and people with intellectual disability. The study appears in The American Journal of Psychiatry.
Why it matters
- Provides molecular evidence that may relate to the excitatory/inhibitory signaling hypothesis of autism.
- Identifies mGlu5 receptor availability as a measurable brain difference that could guide mechanistic research.
- Suggests EEG could serve as a more accessible correlate of molecular findings, potentially aiding larger studies.
- Points to mGlu5 as a potential therapeutic target, while recognizing many autistic people do not seek medication.
Key facts
- Study compared 16 autistic adults with 16 neurotypical adults using MRI and PET imaging.
- Researchers report lower availability of metabotropic glutamate receptor 5 (mGlu5) across autistic participants.
- Fifteen autistic participants also underwent EEG; EEG measures were associated with lower mGlu5 availability.
- Authors frame findings within the excitatory/inhibitory signaling imbalance hypothesis for autism.
- All autistic participants had average or above-average cognitive abilities.
- Results published in The American Journal of Psychiatry.
- PET imaging is costly and involves radiation exposure, which has limited prior studies in children.
- Yale investigators are developing lower-radiation PET techniques to enable studies in younger people and those with intellectual disability.
- There are currently no medications that treat core difficulties of autism; researchers say findings could inform future therapeutic development.
What to watch next
- Planned follow-up studies using lower-exposure PET to examine children and adolescents for developmental patterns.
- Work to validate EEG measures as an accessible marker linked to mGlu5 function in larger, diverse cohorts.
- Research efforts to include people with intellectual disabilities using adapted PET approaches.
- Preclinical or clinical efforts testing therapeutics that target the mGlu5 receptor as a potential intervention for symptoms affecting quality of life
Quick glossary
- mGlu5 receptor: A type of metabotropic glutamate receptor involved in modulating neuronal signaling; one of several receptors responsive to glutamate.
- Glutamate: The brain’s primary excitatory neurotransmitter, which promotes neuronal activation in many circuits.
- Positron emission tomography (PET): A molecular imaging technique that uses radioactive tracers to visualize biochemical processes in the body.
- Electroencephalography (EEG): A noninvasive method that records electrical activity from the scalp to assess brain function.
- Excitatory/inhibitory balance: The equilibrium between neural signals that promote activity (excitatory) and those that suppress it (inhibitory), important for normal brain function.
Reader FAQ
Does this study prove that mGlu5 differences cause autism?
Not confirmed in the source. The researchers state it is unclear whether lower mGlu5 availability is a cause or a consequence of living with autism.
Will this lead to a diagnostic blood test or scan for autism?
Not confirmed in the source. Authors suggest molecular markers could inform future diagnostics, but no diagnostic test is reported.
Were children included in the study?
No. The current study included only autistic adults; the team plans future work in children using lower-exposure PET methods.
Could this result change treatment options now?
Not confirmed in the source. Researchers say the finding points to mGlu5 as a possible therapeutic target, but development and testing of treatments are future steps.
NEW RESEARCH QUICK READ Researchers Discover Molecular Difference in Autistic Brains By Isabella Backman December 19, 2025 5 Minute Read Share Listen to this article 00:00 06:10 Yale School of…
Sources
- Researchers discover molecular difference in autistic brains
- Imaging Metabotropic Glutamate Receptor 5 and Excitatory …
- Lower mGlu5 Availability Linked to Altered Neural Activity …
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