Normal Neurulation in Mammals

  1. Gregory Bock and
  2. Joan Marsh
  1. Gillian Morriss-Kay,
  2. Heather Wood and
  3. Wei-Hwa Chen

Published Online: 28 SEP 2007

DOI: 10.1002/9780470514559.ch4

Ciba Foundation Symposium 181 - Neural Tube Defects

Ciba Foundation Symposium 181 - Neural Tube Defects

How to Cite

Morriss-Kay, G., Wood, H. and Chen, W.-H. (2007) Normal Neurulation in Mammals, in Ciba Foundation Symposium 181 - Neural Tube Defects (eds G. Bock and J. Marsh), John Wiley & Sons, Ltd., Chichester, UK. doi: 10.1002/9780470514559.ch4

Author Information

  1. Department of Human Anatomy, University of Oxford, South Parks Road, Oxford OX1 3QX, UK

Publication History

  1. Published Online: 28 SEP 2007

ISBN Information

Print ISBN: 9780471941729

Online ISBN: 9780470514559



  • normal neurulation;
  • retinoic acid receptors;
  • presomitic hindbrain;
  • morphogenesis;
  • mammals


During mammalian neurulation regional differences are evident between the cranial region, in which neurulation is most complex, the trunk as far as the caudal neuropore and the secondary neurulation region of the caudal trunk plus tail. Differences among these three regions are characterized by specific patterns of morphogenesis and by specific patterns of gene expression. During cranial neurulation distinct regions develop in the brain and the presomitic hindbrain forms seven rhombomeric divisions. The first clear morphological boundary is the preotic sulcus (later transformed into the gyms between rhombomeres 2 and 3), which may limit cell movement as neuroepithelial cells rostra1 to it flow towards and into the rapidly expanding forebrain region. The formation of rhombomeres as morphological entities and the development of a normal rhombomere-specific pattern of homeobox and other gene expression domains depend on relatively low levels of retinoic acid. Retinoic acid receptors, which are retinoic acid-activated transcription factors, and retinoid binding proteins, which control the availability of retinoic acid to the receptors, show regional patterns of expression in the cranial, trunk and caudal regions of the neuroepithelium during neurulation. These patterns suggest a possible mechanism for region-specific gene expression during neurulation.