Autism and Cortical Thickness Deviation From Neurotypical Controls: Evidence for a Spatial Association With Serotonin Receptors.
Cortical thickness gaps in autism follow the serotonin receptor map, pointing to new drug targets.
01Research in Context
What this study did
Tarchi et al. (2026) scanned autistic and neurotypical brains with MRI. They mapped where the cortex was thicker or thinner in autism. Then they overlaid a second map showing where serotonin receptors sit.
The team asked: do the spots with the biggest thickness gaps line up with the spots rich in serotonin receptors? They also checked whether bigger gaps went hand-in-hand with social-communication scores.
What they found
The thickness gaps in autism lined up almost perfectly with the serotonin receptor map. Bigger gaps tracked with more social-communication struggles.
In short, the parts of the brain that look different in autism are the same parts that use serotonin the most.
How this fits with other research
Oblak et al. (2013) cut open autism brains and counted fewer serotonin receptors in social-emotional areas. Livio now shows the living brain is shaped differently in those exact zones.
Griffith et al. (2012) already linked thicker anterior cingulate to worse social scores. Livio keeps that link but adds the serotonin twist, showing the thickness gap sits where receptors should be.
Ecker (2017) reviewed earlier cortical thickness work and said biomarkers were still experimental. Livio pushes the field forward by giving those thickness maps a chemical address—serotonin.
Why it matters
You now have a brain-based reason to watch for serotonin-linked behaviors. If a client has strong social-communication needs, ask the prescribing doctor whether a serotonergic drug targets the mapped regions. You can also track social progress while doctors adjust dose, adding data to the team.
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02At a glance
03Original abstract
Cortical thickness (CT) differences between autistic individuals (AI) and neurotypical controls have been consistently reported, yet the neurochemical mechanisms underlying these differences remain insufficiently understood. Neurotransmitter receptor systems exhibit distinct spatial distributions across the cortex and influence synaptic maturation, plasticity, and cortical organization. Consequently, mapping CT deviations onto these receptor density gradients provides a biologically informed framework for investigating the potential underlying neurochemical architectures of observed structural patterns in autism. A total of 1035 structural MRIs (AI n = 505, neurotypical controls n = 530) were included from Autism Brain Imaging Data Exchange (ABIDE). Group contrasts and individual-level deviations from age-predicted CT patterns were computed. These spatial patterns were correlated with neurotransmitter receptors cortical density distributions (D1, D2, 5HT1a, 5HT2a, 5HT4, 5HT6, mGluR5) from previous PET studies. Widespread vertex-wise deviations in CT were observed in AI in comparison to neurotypical controls. At the group level, CT differences were spatially aligned with the cortical density of serotonin receptors (5HT1a: r = 0.22, FDR-p = 0.032; 5HT4: r = 0.21, FDR-p = 0.032). At the individual level, greater deviations from predicted CT, if mapped onto specific neurotransmitter receptor density gradients, correlated with greater difficulties in the social and communication domains. The findings provide novel evidence that serotonin receptors may play a role in shaping cortical structural brain differences between AI and neurotypical controls. The link between CT differences and spatial distributions of the serotoninergic system offers a translational perspective for future targeted support strategies focused on serotonergic pathways.
Autism research : official journal of the International Society for Autism Research, 2026 · doi:10.1002/aur.70243