An Association Between Serotonin 1A Receptor, Gray Matter Volume, and Sociability in Healthy Subjects and in Autism Spectrum Disorder.
In adults with ASD, the normal lock-step between serotonin receptors, putamen size, and sociability breaks down.
01Research in Context
What this study did
Lefevre et al. (2020) scanned 40 men. Half had autism, half were neurotypical.
They used PET to map serotonin 1A receptors and MRI to measure gray-matter volume.
Each man also filled out a sociability questionnaire.
What they found
In typical men, more serotonin 1A receptor density matched bigger putamen volume and higher sociability scores.
In autistic men, this link disappeared. Receptor density and volume still existed, but they no longer tracked together.
How this fits with other research
Storch et al. (2012) saw no routine MRI differences in high-functioning kids with autism. That seems opposite, but their scans looked only at large shapes, not chemical links.
Capio et al. (2013) showed that even typical adults with mild autism traits have tiny gray-matter shifts. Arthur’s team extends this by adding serotonin to the picture.
Eussen et al. (2016) found wide white-matter problems in autistic youth. Together, the studies suggest brain structure and chemistry disconnect at multiple levels.
Why it matters
If serotonin 1A receptor density no longer couples with social brain volume, drugs or behavioral plans that boost serotonin might reopen this link. When you write social skills goals, remember the biology may need support too.
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02At a glance
03Original abstract
Central serotonin is an important molecular pathway, involved in the regulation of social behavior and gray matter volume (GMV). In men with autism spectrum disorders (ASD), the serotonergic system and the GMV have been found disrupted. Here, we investigated the relation between serotonin, GMV, and social personality in men with typical development (TD) and in men with ASD. We combined anatomical magnetic resonance imaging, Positron emission tomography scan with 2'-methoxyphenyl-(N-2'-pyridinyl)-p-18F-fluoro-benzamidoethylpiperazine radioligand and revised NEO personality inventory personality questionnaire to examine the association between serotonin 1A receptor (5-HT1A R) binding potential, GMV and social personality in 24 adult male TD subjects and 18 male men with ASD. In both groups, we found a positive correlation between 5-HT1A R binding potential and GMV in a region dependent manner. In the TD group, we observed a negative correlation between 5-HT1A R and GMV in the left and right posterior putamen. 5HT1A R binding and GMV in the putamen further correlated with social personality scores in the TD group. None of these associations were found in men with ASD, although no differences were observed for 5-HT1A R concentration among the two groups. Our findings point to a deregulation of 5-HT1A R density in the striatum of men with ASD, a failure that might contribute to their social disturbances. Serotonin is suspected to be involved in the pathophysiology of autism. We provide evidence for a role of serotonin 1A receptor in social behavior through a specific regulation of GMV in the putamen region in neurotypical subjects but not in men with autism. This suggests a potential impairment of the serotonergic system in men with autism which may contribute to patients' social disturbances. Our findings suggest further investigation on the role of serotonin 1A receptor and its activity in the striatum to regulate social behavior. Autism Res 2020, 13: 1843-1855. © 2020 International Society for Autism Research and Wiley Periodicals LLC LAY SUMMARY: Serotonin is suspected to be involved in the pathophysiology of autism. We provide evidence for a role of serotonin 1A receptor in social behavior through a specific regulation of gray matter volume in the putamen region in neurotypical subjects but not in men with autism. This suggests a potential impairment of the serotonergic system in men with autism which may contribute to patients' social disturbances. Our findings suggest further investigation on the role of serotonin 1A receptor and its activity in the striatum to regulate social behavior.
Autism research : official journal of the International Society for Autism Research, 2020 · doi:10.1002/aur.2360