Anatomy and Embryology

, Volume 201, Issue 3, pp 169–179

The early development of thalamocortical and corticothalamic projections in the mouse

  • Carme Auladell
  • Pol Pérez-Sust
  • Hans Supèr
  • Eduardo Soriano
Original Article

DOI: 10.1007/PL00008238

Cite this article as:
Auladell, C., Pérez-Sust, P., Supèr, H. et al. Anat Embryol (2000) 201: 169. doi:10.1007/PL00008238

Abstract 

The initial ingrowth of corticothalamic and thalamocortical projections was examined in mice at embryonic and perinatal stages. Fibers, in fixed brains, were labeled with the carbocyanine dye 1,1’-dioctadecyl-3,3,3’,3’-tetramethylindocarbocianine perchlorate (DiI). By E13, the corticofugal fibers had entered the lowest intermediate zone through which they ran, turned over the corpus striatum, and left the cortex. The fibers were arranged in scattered bundles throughout the corpus striatum. At E14 corticofugal axons reached the internal capsule and at E14.5–E15 they established contact within the thalamus. Meanwhile, the thalamocortical afferents reached the neocortex at E13. At this time fibers ran tangentially within the intermediate zone, immediately underneath the cortical plate. By E14, the fibers had started to invade the subplate and, by E15, thalamocortical fibers had begun their radial growth into the cortex. Such radial growth proceeded steadily, invading each cortical layer as it differentiated cytoarchitectonically from the dense cortical plate. The first retrogradely labeled cells were detected at the cortical plate at E15. By the day of birth (E20), thalamocortical fibers had formed a dense branching system within layers VI and V. Our observations indicate that, in mice, the thalamic axons reach the cortex before corticothalamic projections enter the thalamic nuclei. Moreover, the results suggest that the pathway followed by each fiber system is different. By DiI injections into the internal capsule we have also determined that subplate cells are the first to send axons to the thalamus.

Key words DevelopmentSubplate neuronsNeocortexThalamusInitial connectivity

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Carme Auladell
    • 1
  • Pol Pérez-Sust
    • 1
  • Hans Supèr
    • 1
  • Eduardo Soriano
    • 1
  1. 1.Department of Animal and Plant Cell Biology, Faculty of Biology, University of Barcelona, Diagonal 645, E-08028 Barcelona, Spain e-mail: carmea@porthos.bio.ub.es Tel.: 34-93-4021551, Fax: 34-93-4112967ES