Conserved Developmental Algorithms During Thalamocortical Circuit Formation in Mammals and Reptiles

  1. Gregory R. Bock and
  2. Gail Cardew
  1. Zoltán Molnár

Published Online: 29 APR 2008

DOI: 10.1002/0470846631.ch11

Evolutionary Developmental Biology of the Cerebral Cortex: Novartis Foundation Symposium 228

Evolutionary Developmental Biology of the Cerebral Cortex: Novartis Foundation Symposium 228

How to Cite

Molnár, Z. (2000) Conserved Developmental Algorithms During Thalamocortical Circuit Formation in Mammals and Reptiles, in Evolutionary Developmental Biology of the Cerebral Cortex: Novartis Foundation Symposium 228 (eds G. R. Bock and G. Cardew), John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/0470846631.ch11

Author Information

  1. Institut de Biologie Cellulaire et de Morphologie, Université de Lausanne, Lausanne, Switzerland

Publication History

  1. Published Online: 29 APR 2008
  2. Published Print: 22 MAY 2000

Book Series:

  1. Novartis Foundation Symposia

Book Series Editors:

  1. Novartis Foundation

ISBN Information

Print ISBN: 9780471979784

Online ISBN: 9780470846636

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Keywords:

  • thalamocortical development;
  • cerebral cortex;
  • thalamus;
  • reeler;
  • L1;
  • transgenic;
  • mouse;
  • forebrain

Summary

The general patterns of early thalamocortical development follow a similar sequence in all mammals. Thalamocortical projections descend through the ventral thalamus, advance in the internal capsule amongst cells which already possess dorsal thalamic projections, then reach the cerebral cortex by associating with subplate cells and their early corticofugal projections. Initially, the thalamic projections pause in the internal capsule and subplate layer. The interactions of the thalamocortical projections with the early generated, largely transient cells of the subplate, marginal zone, internal capsule and ventral thalamus are believed to play a crucial role in the organized deployment of thalamic projections and establishing a functional cortical architecture. Selective fasciculation, contact guidance and release of neurotrophic factors are thought to play roles in the development of thalamocortical projections. These ideas are obtaining support from recent work on reeler and other strains of mice. The evolutionary origin of these largely transient cells and the overlying logic of early developmental steps are not understood. The behaviour of the thalamocortical and corticothalamic projections at the corticostriatal junction is particularly puzzling. The comparison of early forebrain development in mammals and reptiles is beginning to reveal highly conserved cellular and molecular interactions during early thalamocortical development and to reveal homologies between telencephalic subdivisions.