Branching pattern of corticothalamic projections from the somatosensory cortex during postnatal development in the rat

C. Frassoni, P. Arcelli, M. C. Regondi, M. Selvaggio, S. De Bias, R. Spreafico

Research output: Contribution to journalArticlepeer-review

Abstract

In adult animals corticothalamic (CT) axons pass through the thalamic reticular nucleus (Rt) where they give off collateral branches innervating the Rt neurons. The postnatal development of CT projections from the somatosensory cortex, with particular reference to the branching pattern within Rt, ventrobasal (VB) and posterior (PO) nuclei, was investigated in the rat with anterograde tracing. Biotinylated dextran-amine (BDA) was iontophoretically injected into the somatosensory cortex of rats ranging from postnatal day (P) 0 to P30. At P1 most of the cortical axons traversed unbranched Rt and terminates in VB and PO, whereas at P3 they formed rudimentary branches in these nuclei. From P6 to P9 a progressive increase in the amount of dense clusters of terminal arborizations was evident in Rt, and by the second postnatal week more complex arborizations with a clear topographic arrangement were observed in Rt, VB and PO. Our findings indicate that CT fibers show a quantitative increase both in Rt and in somatosensory thalamic nuclei during the first postnatal week, although their terminal arborizations are however still incomplete. The pattern of collateralization of CT projections achieves an adult configuration at the end of the second postnatal week.

Original languageEnglish
Pages (from-to)111-121
Number of pages11
JournalDevelopmental Brain Research
Volume90
Issue number1-2
DOIs
Publication statusPublished - Dec 21 1995

Keywords

  • Biotinylated dextran amine
  • Corticothalamic
  • Posterior nucleus
  • Postnatal development
  • Thalamic reticular nucleus
  • Ventrobasal nucleus

ASJC Scopus subject areas

  • Developmental Biology
  • Developmental Neuroscience

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