Imaging, anatomical, and molecular analysis of callosal formation in the developing human fetal brain

Tianbo Ren, Aurora Anderson, Wei Bin Shen, Hao Huang, Celine Plachez, Jiangyang Zhang, Susumu Mori, Stephen L. Kinsman, Linda J. Richards

Research output: Contribution to journalArticle

Abstract

A complex set of axonal guidance mechanisms are utilized by axons to locate and innervate their targets. In the developing mouse forebrain, we previously described several midline glial populations as well as various guidance molecules that regulate the formation of the corpus callosum. Since agenesis of the corpus callosum is associated with over 50 different human congenital syndromes, we wanted to investigate whether these same mechanisms also operate during human callosal development. Here we analyze midline glial and commissural development in human fetal brains ranging from 13 to 20 weeks of gestation using both diffusion tensor magnetic resonance imaging and immunohistochemistry. Through our combined radiological and histological studies, we demonstrate the morphological development of multiple forebrain commissures/decussations, including the corpus callosum, anterior commissure, hippocampal commissure, and the optic chiasm. Histological analyses demonstrated that all the midline glial populations previously described in mouse, as well as structures analogous to the subcallosal sling and cingulate pioneering axons, that mediate callosal axon guidance in mouse, are also present during human brain development. Finally, by Northern blot analysis, we have identified that molecules involved in mouse callosal development, including Slit, Robo, Netrin1, DCC, Nfia, Emx1, and GAP-43, are all expressed in human fetal brain. These data suggest that similar mechanisms and molecules required for midline commissure formation operate during both mouse and human brain development. Thus, the mouse is an excellent model system for studying normal and pathological commissural formation in human brain development.

Original languageEnglish (US)
Pages (from-to)191-204
Number of pages14
JournalAnatomical Record - Part A Discoveries in Molecular, Cellular, and Evolutionary Biology
Volume288
Issue number2
DOIs
StatePublished - Feb 1 2006

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Keywords

  • Axon guidance
  • Commissure
  • Diffusion tensor magnetic resonance imaging
  • Npn1
  • Pioneering axons
  • Robo
  • Slit

ASJC Scopus subject areas

  • Anatomy
  • Agricultural and Biological Sciences (miscellaneous)

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