Anterior and posterior commissures in agenesis of the corpus callosum: Alternative pathways for attention processes?

Vanessa Siffredi*, Amanda G. Wood, Richard J. Leventer, Maarten Vaessen, Alissandra McIlroy, Vicki Anderson, Patrik Vuilleumier, Megan M. Spencer-Smith

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Developmental absence (agenesis) of the corpus callosum (AgCC) is a congenital brain malformation resulting from disruption of corpus callosum formation, a structure that is crucial for the transfer and integration of information, including attention processes, across the brain. This study aimed to investigate previously proposed candidates for alternative inter-hemispheric pathways in AgCC by examining (1) white matter volume and microstructure of the anterior and posterior commissures in children with AgCC compared to typically developing controls (TDC), and (2) in children with AgCC, examine the associations of white matter volume and microstructure of the anterior and posterior commissures and any remaining corpus callosum with attention processes. Participants were 21 children with AgCC (13 complete, 8 partial) recruited from The Royal Children's Hospital, Melbourne, and 30 TDC aged 8–17 years. T1-and diffusion-weighted MR sequences were used to calculate volume and microstructural parameters. Neuropsychological testing assessed attention processes. We found the anterior commissure was significantly larger in volume in children with AgCC than TDC (p = .027), with reduced mean FA (p = .001) associated with increased mean RD (p < .001). In children with AgCC, we found microstructural properties of the anterior commissure associated with attentional processes, specifically, mean FA of the anterior commissure was associated with better divided attention (p = .03), and the association between alerting attention and mean AD and RD was found to be moderated by age (p = .027, p = .008) and the degree of corpus callosum agenesis (p = .025, p = .016). Furthermore, in partial AgCC, larger posterior commissure volume was associated with better orienting attention (p = .035). In conclusion, we provide evidence that the volume and microstructure of the anterior commissure are altered in children with AgCC, and this neuroplastic response might have an influence on attention processes.
Original languageEnglish
Pages (from-to)454-467
Number of pages14
JournalCortex
Volume121
DOIs
Publication statusPublished - Dec 2019

Keywords

  • Agenesis of the corpus callosum
  • Alternative inter-hemispheric pathway
  • Anterior and posterior commissures
  • Attention processes
  • Development
  • WHITE-MATTER MICROSTRUCTURE
  • WORKING-MEMORY CAPACITY
  • INTERHEMISPHERIC-TRANSFER
  • HUMAN BRAIN
  • NEUROPSYCHOLOGICAL PROFILE
  • CEREBRAL LATERALIZATION
  • SUSTAINED ATTENTION
  • NATIONAL CURRICULUM
  • VOXELWISE ANALYSIS
  • PARIETAL CORTEX

Cite this

Siffredi, V., Wood, A. G., Leventer, R. J., Vaessen, M., McIlroy, A., Anderson, V., Vuilleumier, P., & Spencer-Smith, M. M. (2019). Anterior and posterior commissures in agenesis of the corpus callosum: Alternative pathways for attention processes? Cortex, 121, 454-467. https://doi.org/10.1016/j.cortex.2019.09.014