Fibroblast Growth Factor 8 Regulates Neocortical Guidance of Area-Specific Thalamic Innervation

Thalamic innervation of each neocortical area is vital to cortical function, but the developmental strategies that guide axons to specific areas remain unclear. We took a new approach to determine the contribution of intracortical cues. The cortical patterning molecule fibroblast growth factor 8 (FG...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of neuroscience 2005-07, Vol.25 (28), p.6550-6560
Main Authors: Shimogori, Tomomi, Grove, Elizabeth A
Format: Article
Language:English
Subjects:
Animals
Axons - ultrastructure
Development/Plasticity/Repair
Electroporation
Fibroblast Growth Factor 8 - genetics
Fibroblast Growth Factor 8 - physiology
Genes, Reporter
Genetic Vectors - administration & dosage
Genetic Vectors - genetics
Injections, Intraventricular
Mice
Neural Pathways - embryology
Neural Pathways - growth & development
Receptor, Fibroblast Growth Factor, Type 3 - genetics
Receptor, Fibroblast Growth Factor, Type 3 - physiology
Recombinant Fusion Proteins - physiology
Somatosensory Cortex - embryology
Somatosensory Cortex - growth & development
Telencephalon - embryology
Telencephalon - growth & development
Thalamus - embryology
Thalamus - growth & development
Transfection
Vibrissae - innervation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Thalamic innervation of each neocortical area is vital to cortical function, but the developmental strategies that guide axons to specific areas remain unclear. We took a new approach to determine the contribution of intracortical cues. The cortical patterning molecule fibroblast growth factor 8 (FGF8) was misexpressed in the cortical primordium to rearrange the area map. Thalamic axons faithfully tracked changes in area position and innervated duplicated somatosensory barrel fields induced by an ectopic source of FGF8, indicating that thalamic axons indeed use intracortical positional information. Because cortical layers are generated in temporal order, FGF8 misexpression at different ages could be used to shift regional identity in the subplate and cortical plate either in or out of register. Thalamic axons showed strikingly different responses in the two different conditions, disclosing sources of positional guidance in both subplate and cortical plate. Unexpectedly, axon trajectories indicated that an individual neocortical layer could provide not only laminar but also area-specific guidance. Our findings demonstrate that thalamocortical axons are directed by sequential, positional cues within the cortex and implicate FGF8 as an indirect regulator of thalamocortical innervation.
ISSN:0270-6474
1529-2401
DOI:10.1523/JNEUROSCI.0453-05.2005