Evidence map›Paper›PMID 41131636›Full record

ArticleMolecular autism2025

Age-related differences in axon pruning and myelination may alter neural signaling in autism spectrum disorder.

Kari L Hanson, Thomas Avino, Sandra L Taylor, Karl D Murray, Cynthia M Schumann

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In one paragraph

Article in Molecular autism, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

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2 · The registry

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3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Kari L HansonDepartment of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Sacramento, CA, USA.
Thomas AvinoMIND Institute, School of Medicine, University of California, Davis, 2805 50th St, Sacramento, CA, 95817, USA.
Sandra L TaylorDepartment of Public Health Sciences, School of Medicine, University of California, Davis, CA, USA.
Karl D MurrayDepartment of Physiology and Membrane Biology, School of Medicine, University of California, Davis, CA, USA.
Cynthia M SchumannMIND Institute, School of Medicine, University of California, Davis, 2805 50th St, Sacramento, CA, 95817, USA. cschumann@ucdavis.edu.

Funding

Axonal Ultrastructure of Temporal White Matter in AutismR03MH104735 · NIMH · UNIVERSITY OF CALIFORNIA AT DAVIS · PI SCHUMANN, CYNTHIA · 2014 to 2015
$156k
Eunice Kennedy Shriver National Institute of Child Health and Human Development P50HD103526NIMH NIH HHS R03MH104735
6 · The paper itself

Abstract

backgroundNeuronal connectivity is refined throughout development by the proliferation and pruning of axons in cerebral white matter, and progressive axon myelination that enables rapid communication across brain regions. Differences in connectivity have been observed in autism spectrum disorder (ASD), including changes in white matter volume and connectivity. In the prefrontal cortex, this includes imbalances between short- and long-ranging axons, consistent with a pattern of local hyperconnectivity, and long-range hypoconnectivity. Alterations in temporal lobe white matter development-critical for social behavior-may contribute to atypical neural connectivity.

methodsWe used electron microscopy to analyze 54 samples of temporal lobe white matter from 27 age-matched postmortem brains from males with ASD and neurotypical (NT) controls, ages 2-44 years. Defined regions of superficial (SWM) and deep (DWM) white matter were sampled from superior temporal (STG) and fusiform (FG) gyri. Axon density and myelin thickness were quantified, with axon size classified by inner diameter, to evaluate age-related differences between ASD and neurotypical brains.

resultsIn neurotypical control brains, total axon density significantly decreases with age in both STG and FG SWM. Although ASD cases show a similar trend, the density of small axons in STG is significantly higher than in controls. However, FG SWM in ASD shows no significant change in small-diameter axon density with age in this region. In neurotypical brains, myelin thickness of large-diameter axons increases significantly with age in STG and FG SWM. In contrast, large-diameter axons in ASD display significantly thinner myelin sheaths than controls across both STG and FG regions.

conclusionsThe temporal lobe exhibits atypical patterns of white matter development in ASD. In neurotypical individuals, decreased axon density in SWM with age reflects effective neural pruning and refinement of local and short-range connectivity. In contrast, individuals with ASD maintain a high density of small-diameter axons in STG SWM, suggesting reduced pruning that results in local overconnectivity. Moreover, myelin thickness in SWM does not increase with age in ASD, implying reduced efficacy of neurotransmission. These alterations in white matter ultrastructure may contribute to the atypical connectivity and neural communication observed in ASD across the lifespan.

Indexed as

AgingAutism Spectrum DisorderAxonsMyelin SheathAdolescentAdultAge FactorsChildChild, PreschoolHumansMaleSignal TransductionTemporal LobeWhite MatterYoung AdultAutismAxon densityBrain developmentMyelinWhite matter

Identifiers

PMID41131636
PMCPMC12548170

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.